Saving Moore’s Law With High-k Materials

It has been more than 4 decades, but Moore’s Law is still relevant and the leading semi-conductor companies, along with their suppliers, are moving forward with breakthrough advancements in materials, processes and fabrication technologies. I was quite fascinated by some of these developments as I read the cover story in the July 9, 2007 issue of C&E News. There is tremendous excitement about “high-k” (high dielectric constant) materials for their potential use as transistor gate insulators in semi-conductor chips.

Early this year, Intel announced the successful commercial development of a 45-nm transistors using new high-k materials and metal gates. The current state-of-the art process is the 65 nm process which Intel uses in the current generation of Core(TM) and Core2 microprocessors. Commercial production for the 45-nm transistors is on track for the second half of 2007 in Fab 32 at Ocotillo, Arizona (under construction) and Fab 28 in Israel (first half of 2008). IBM and Advanced Micro Devices have also announced similar plans for first quarter of 2008.

Silicon dioxide is currently used as the gate insulator material (k=4.2). Shrinking chip size forces the gate oxide layer to be thinner, which has now been reduced to below 2 nm in the current transistors. At this level, chip performance is compromised due to electron leakage across the thin gate insulator. According to Intel’s press release, transistor gate leakage associated with the ever-thinning gate dielectric made of SiO2 has been recognized by the industry as one of the most formidable technical challenges facing Moore’s Law in this decade.

Hafnium based high-k materials provide a solution to this problem by allowing a thicker layer of the gate insulator to be used in the transistor which solves the leakage problem and facilitates high performance. However, before this technology can be implemented, two associated problems need to be solved:

• A suitable precursor which can be applied on silicon using an appropriate technique that can be integrated with the current process, and;
• A metal-based gate electrode which can replace the currently used polysilicon material

Intel seems to have solved both of these problems, however the specific details of the materials and process recipe are trade secrets. Here is a sketch of their High-k + Metal Gate Transistor:

Excellent details are provided in a presentation by Mark Bohr, a Senior Fellow in Intel’s Logic Technology and Development Group.

Texas Instrument has provided a glimpse of this technology by disclosing that their high-k material in SoC processors for wireless products will be hafnium silicon oxynitride (HfSiON), which is formed by depositing hafnium silicon oxide and then reacting it with nitrogen plasma. Here is an excerpt from their press release, which highlights the success of this technology:

Through a modular addition to the typical CMOS gate stack process, HfSiON integration has been demonstrated offering mobility that is 90 percent of the silicon dioxide universal mobility curve, with effective oxide thicknesses (EOTs) below 1-nm. These results were accomplished without sacrificing reliability or adding significant cost to the CMOS process. Precise tuning of the film composition, tight controls, and high throughput also make HfSiON suitable for high volume manufacturing.

Hafnium oxide has a dielectric constant of about 30, however it is a challenging material to integrate into a silicon-based semiconductor. HfSiON seems to be a good compromise material although the dielectric constant is lower. We can expect to see continued development of these materials to optimize the balance of performance and large scale manufacturability.

European Bioplastics – A Promising Industry Association

I am quite impressed by the industry association European Bioplastics – an association of about 68 members ranging from bioplastics manufacturers, converters, end users, research groups and machinery suppliers. Registered in 2006 as a successor to the “International Biodegradable Polymers Association and Working Groups” (IBAW), its main mission is to support and promote market introduction of bioplastics. In particular, I liked their balanced approach reflected by the maxim “promote bioplastics rather than discriminate against conventional plastics”. Certainly, a key aspect of their strategy is to lobby for subsidies that can promote mass commercialization of bioplastics and lower risks for the much-needed investment of several billion euros in manufacturing capacities and infrastructure. To this effect, they have proposed several ideas on potential subsidies/developmental opportunities under Framework Conditions.

Although bioplastics account for only 1% of the total current plastics consumption in Europe, they are estimated to have the potential of nearly 4 million tons; i.e. about 10% of the current total market. This is huge – it translates to about 9 billion pounds, which nearly equals the estimated 9.7 billion pounds of low density polyethylene film for packaging applications (see my previous post) by 2010. Even if only 50% of this potential is eventually realized, it will still be about 10 times higher than what is projected for the US market for bioplastics by 2010. Therefore, the projected demand in Europe is much higher than anywhere else in the world.

There seem to be a few major trends driving this demand:

• Environmentally sensitive consumer population willing to pay a little more for products made from renewable sources
• Companies responding to the consumer sentiments by creating an image of sustainable development through such products
• Government regulations such as the EU landfill directive and German packaging directive, plus the overall EU political strategies on renewable resources and recycle
• Sharp rise in material and energy prices, not to mention the extreme volatility arising from crude oil prices

Contrast this to the near-term projected capacity for PLA and starch-based bioplastics. According to my post “Bioplastics Production Capacity Building Up” of May 12, the total projected production capacity of PLA and starch polymers is not even 5% of this ultimate demand of 4 million tons! Also, strangely enough, most of the PLA capacity is being established in the US, while a majority of the demand is projected in Europe (or even Japan). How come investment is not flowing into the EU for new capacity in bioplastics? Are these projections realistic?

I am hoping that the European Bioplastics will provide better research in future so we can gain a better understanding of this interesting market dynamics.

Strong Growth Projections for Bioplastic Film Packaging

The June 2007 issue of Plastics Engineering provides several interesting facts about the demand, usage and production of bioplastics in the cover story. Quoting a Freedonia Group report (Degradable Plastics, September 2006), it estimates that the demand for biodegradable and compostable plastics in the U.S. is expected to increase 20% per year through 2010. Led by polylactic acid (PLA) and starch-based bioplastics, the total volume by 2010 is estimated to be around 420 million pounds. Packaging industry presents the best opportunity for these materials in applications such as films, bottles and food service products.

Contrast that to the following growth projections for some of the major plastics film markets (see Freedonia Report Plastic Film, August 2006):

• Low density polyethylene film used in produce and snack packaging, shrink wraps and trash bags: 2.8% per year growth to 9.7 billion lbs by 2010
• Polypropylene film used in produce, grain mill and dairy products packaging: 3.4% per year to 1.5 billion lbs by 2010

Certainly, market growth rates for bioplastic film packaging are significantly higher than those for the conventional plastics, although the total market is still quite small. In order to compete with low density polyethylene and polypropylene, PLA and starch-based bioplastics will need to be cost-effective on both resin and film processing costs. Although, petroleum-based plastics have recently seen various price increases/volatility and supply interruptions, cost of corn-derived bioplastic such as PLA is still sky-high in comparison. According to one estimate, currently PLA is at an average of $1.3/lb, which is expected to fall below $1/lb within a year as more capacity becomes available. Still, there is considerable risk to PLA cost due to volatility in corn and energy prices. Starch-based bioplastics are likely to be less expensive; however they too are not immune to rising energy prices. Therefore, resin cost is likely to remain a key barrier for growth of these bioplastics.

Despite the cost challenge, several interesting examples of packaging applications are emerging. A few are listed below:

• Biophan(R) crystal-clear PLA film from Treofan GmbH for food packaging
• BIOTA (Blame It On The Altitude) water bottles (Naturworks PLA)
• NaturallyIowa Milk bottles (Natureworks PLA)
• PLA bottles in the German drugstore IhrPlatz (drinking water)
• Earthfirst(R) PLA film for various applications
• Clear oxide barrier coating on PLA film for oxygen-sensitive packaging

McKinsey Global Survey on Corporate Investing Decisions

A global surevey of 2500 executives from around the world provides an interesting perspective on how investment decisions are made in companies and how these decisions often go wrong despite the best efforts of a lot of smart people. The good news is that most companies follow a rigorous review process with senior executives, including the CEOs, who pay close attention to all the right criteria such as past performance of the business units and value creation potential of the proposed projects. Still, it is quite shocking to note the following statistics:

• Funding the wrong projects: Overall, those who responded, admitted that nearly 20% of their capital investments over the last 3 years were a mistake which should not have been approved. 23% of those who responded believed that more than 25% of their approved capital had gone to underperforming projects that should now be discontinued
• Not funding the right projects: Corporate level executives, who responded, believed that it was a mistake not to approve 21% of the rejected investments over the last 3 years

It appears that roughly 1 in every 4 or 5 capital investment decision is often incorrect. Clearly, this causes a lower return on investment – and even more importantly – results in lost opportunity on projects that could provide a better return. Surely, no one has the perfect crystal ball that could help them make the right decisions all the time. Still, just consider the following observations that seem to be responsible for this low investment efficiency, and it is hard not to feel that there is a lot of room for improvement:

• 40% of the frontline managers do not know their company’s rate of return on recent investments
• Overly optimistic estimates of timing and sales projections on new projects
• Generally risk averse, most companies tend to view a similar level of risk in projects of varying sizes – clearly, either the risks are not well understood, or the risk assessments are not very rigorous
• Projects are evaluated independent of each other. A portfolio-based approach is often missing, which results in a very poor understanding of the overall corporate risk
• 36% of the respondents say that managers hide, restrict or misrepresent information when submitting projects for funding decisions
• Funding decisions made as a result of intense lobbying and politicking.

Although not explicitly outlined in the study, I think the following observations may also have a significant contribution to these results:

• Frontline managers – and to some extent – even the unit-level managers, are usually reluctant to “kill” their projects even though the risks are high and probability of success is low. No one gets promoted by doing that!
• Charisma of the project champion is often more important in getting funding than the detailed analysis of risks/return on the project
• Only select projects are reviewed with senior executives while a lot of other projects continue to drain resources in the background
• Internal rivalries within various business units often result in several overlapping projects that cause duplication of effort

Certainly, there are companies that deliver a much higher return on investment than the average. It would be interesting to learn more about the factors responsible for their success.

Many Players Emerging in the Bioplastics Arena

In a recent search, I came across a nice presentation from Keith Edwards of the BASF company, which was delivered at the May2007 SPI Film & Bag Federation meeting in Florida. The title of the presentation is also quite interesting – “Biodegradable and Renewable Materials: Do they exist? Are they here to stay?“. What caught my eye was the following Table which provides a pretty good list of different companies emerging in the bioplastics arena –

I was already aware of Natureworks, Metabolix, Novamont, Stanelco and BASF as I wrote about them in my post Bioplastics Production Capacity Building Up (May12, 2007). This table provides a much more complete list. Clearly, there are quite a few players in the game and the industry dynamics is beginning to get interesting.

London Celebrates 100 Years of Plastics

It has been 100 years since Leo Baekeland invented Bakelite, and to celebrate this occasion, the Science Museum of London opened a special exhibition this week. Appropriately titled Plasticity – 100 years of making plastics, this exhibition has several interesting displays to showcase the evolution of plastics over the last century:

• Bakelite coffin from wood-flour filled phenol-formaldehyde resin, 1938
• Mold for a Tupperware(R) container, 1965
• Model airplanes with different shapes, some appear to resemble a bird
• Toyota iUnit concept car, 2005. It uses plant-based materials instead of oil-based plastics and metals. Tough kenaf plant fibres are held together by lignin, a natural polymer found in wood.
• GRP Futuro House, 1968
• PVC dress

I am sure there are many more exhibits, this is what I could gather from the web. I hope they are getting a good crowd!

Baekeland was Belgian by birth, but immigrated to USA after completing his doctorate. Most of his inventions happened here in America. So I wonder why this exhibition did not open in an American city.

Certainly, plastics have changed the way we live so much so that we now take it for granted. Here is a nice timeline of plastics that I found on the National Plastics Center & Museum’s website.

Carbon Nanotubes Gaining New Applications In Plastics

New applications of plastic composites based on multi-wall carbon nanotubes (MWNT) are finally emerging according to the cover story in the May 2007 issue of Plastics Engineering. There are three key drivers for this trend:

• New production capacity and lower cost of production (see my post of May 15, 2007)
• Expiration of important patents held by Hyperion Catalysis (for example US patent 4,663,230 issued May 1987)
• A growing number of business and technology partnerships

Two main areas of applications are sports equipment (lighter and stronger composite material) and automotive (static dissipation). Here are a few examples:

• Hockey sticks from the Finnish company Montreal Sports use Baytubes(R) in an epoxy compound. These sticks are reported to be 60 – 70% more impact resistant than carbon fiber composite sticks. According to a page on the company’s website, “Nanotechnology has made it possible to produce a more flexible shaft, which helps the handling of the puck and improves the feel for the game. The most important benefits are the improved manageability and durability“.

• Sailboat mast for the new Synergy 350 RL yacht based on the Nanosolve(R) epoxy-nanotube composite from Zyvex. According to Zyvex’s press release, it replaces a carbon-fiber reinforced fabric bonded together by epoxy.

• Zyvex’s Nanosolve(R) materials are being used in a variety of sporting goods such as bicycles, baseball bats, hockey sticks and golf clubs. According to the Plastics Engineering story, the 2006 US Open winner, Geoff Ogilvy, uses clubs containing Nanosolve(R). See a complete list of Nanosolve(R) applications here.

• Nano In branded nanocomposites from Nanoledge are used in skis called “Nano In Black” from another French company Axunn. These are reported to have better shock resistance and flexibility and are lighter than other brands. Several other applications are under development for Sports & Leisure, Automotive and Aviation sectors.

• Applications in the Automotive and Electronic industries (Reference: paper from Hyperion Catalysis)
  • Fibrils from Hyperion Catalysis are used in the auto industry to dissipate electricity in fuel lines and connectors. Nylon 12 is typically used as the plastic material for these components, to which MWNT is added in low loading levels. Nylon 12 has good resistance to gasoline. Lately, the fuel lines are made of multiple co-extruded layers to comply with hydrocarbon emissions levels according to the Clean Air act.
  • Thermoplastic fenders of high-heat plastic for in-line electrostatic painting in conjunction with steel panels. High conductivity in the plastic part is achieved from these carbon nanotubes.
  • Front Unloading Unified Pods (FOUPS) for transporting silicon wafers from one station to the other are made from engineering plastics such as polycarbonate (PC), polyetherimide (PEI) and polyetheretherketone (PEEK) loaded with carbon nanotubes.

  

• There is also a strong interest in the Aerospace market for nanocomposites of carbon nanotubes. Broadly speaking, carbon nanotubes are considered for use as reinforcements in ultra-lightweight parts. In my research, I came across a presentation from the advanced materials and processing group at NASA (see Enabling Technologies for Aerospace Missions – The Case for Nanotubes). The information in this package is rather futuristic; however it is quite clear that carbon nanotubes are considered to be among the front-runners in the list of available materials. They are expected to enable “radical design changes” by permitting a combination of properties not previously available and multi-functionality for increased efficiency. Among the challenges cited before this promise becomes a reality are inconsistent quality of supply, dispersion issues and limited characterization data for nanocomposites.

 

 

There is enough momentum in the industry, and enough pull in the market, for the technology of carbon nanotubes to eventually mature into a solid, reliable platform. It is only the beginning!

 

 

 

Picket Fence from Recycled Plastic and Wheat Straw

Using recycled Polyethylene (HDPE) from milk jugs and cellulose from wheat straw, a Wyoming company has developed a process to make picket fences that look like wood but have the durability and a maintenance-free benefit of plastic. The latest issue of Plastics Technology reports that Heartland Bioplastics LLC is now marketing its PrairiePicket(R) privacy fence using this process hoping to capture a share of the fast growing residential fence market.

Total US fencing market in 2007 is estimated at $3.3 billion growing at 5% each year, of which 59% is for residential use (2003 note from Dartmouth). Wood and metal are predominant and account for nearly 90% of the sales. Vinyl plastic and wood-plastic composites (WPC) are gaining in popularity although cost remains a major issue. Utilization of recycled plastic and wheat straw should result in lower cost, although I do not know the exact cost of the PrairiePicket fence.

An interesting fact is that one picket (6 ft long by 5 1/8″ wide by 3/8″ thick) takes 12 jugs and that Heartland uses upto 40,000 lbs of plastic a week (See Tom Lacock’s post on Wyospace). Based on this information, I estimate a production rate of about 23000 pickets/week.

Wheat straw is a good source of reinforcement for plastics that melt at low temperatures (less than 200 °C). Good thing is that it is makes up about half of the yield of a cereal crop such as barley, oats, rice, rye or wheat, which means it is available in abundant quantities. Sure, there is a lot of interest in converting the straw cellulose into ethanol as a biofuel, however that technology is in its infancy and only a small amount is produced on a pilot scale. So, there should be plenty of wheat straw available for these applications.

At a 30% loading by weight in polypropylene, wheat straw as a reinforcing filler delivers a modulus of 3.3 GPa, nearly 2.5 times more than virgin polypropylene, and 3-16% incresae in tensile strength and 13 – 48% increae in flexural strength (see paper from the 4th International Conference on Woodfiber-Plastic Composites). However, similar to other filled composites, there is a significant drop in impact strength.

Wheat Straw fibers have an interesting microstructure as shown in this picture. Dr. Vik Malhotra at Southern Illinois University, Carbondale, has been using wheat straw to develop biocomposites for wheat byproduct wallboards. In order to get good reinforcement, it is important to convert wheat straw into fibers of uniform length without causing excessive damage. Heartland, it appears, has developed its own proprietary “dry process” to prepare wheat straw for mixing with recycled HDPE. At 50 – 60% loading, the wheat straw-HDPE composite picket has a flex modulus of 3.3 GPa, similar to the Polypropylene-wheat straw composite described above.

A few more things to keep in mind – it is critical to dry the wheat straw prior to mixing with plastic in a hot extruder. Typically, wheat straw at ambient conditions have about 10 -15% moisture by weight, which must be reduced to less than 1% prior to extrusion. Otherwise, this moisture will steam up and create voids in the final product.

Since wheat straw is a natural material, it can lead to mildew growth. Reportedly, Heartland adds Zinc Borate to prevent mildew. Zinc Borate is also commonly used as a flame retardant in polymers.

Overall, a good use of recycled plastic and a natural biomaterial. Who knows, if you save up enough milk jugs, you might be able to get a free fence!

Bioplastic Converts to Biodiesel After Use

The New York Times reported on this interesting technology on April 9, 2007:

Scientists worldwide are struggling to make motor fuel from waste, but Richard Gross has taken an unusual approach: making a “fuel-latent plastic,” designed for conversion. It can be used like ordinary plastic, for packaging or other purposes, but when it is waste, can easily be turned into a substitute diesel fuel.

Following the original story, several prominent blogs also reported on this interesting technology (See posts on Green Options, Wired Blog Network, Green Brooklyn, FutureSheet). However, it was only recently that I came across this news on the Plastics and Resins blog on CR4‘s Chemical and Material Science section, which I must admit, was a fascinating find!

What I find most interesting is that the packaging material made out of this bioplastic can be converted into fuel after it has been already used and rejected. In this way, it provides value multiple times during its life cycle. Not to mention that the original biopolymer is synthesized using a bioprocess from natural raw materials using enzymes or chemical catalysts.

Prof. Richard Gross, who holds the prestigious Herman F. Mark Chair at the Brooklyn Polytechnic University, has been active in this field for many years. As I read his bio on his website, I was delighted to learn that he had worked with Prof. Robert Lenz at UMass, Amherst (I obtained my PhD from UMass in 1998!). Prof. Lenz, of course, is very well known for his pioneering work with bacterial synthesis of PHA‘s. In 2003, Prof. Gross received the Presidential Green Chemistry Award for his work on lipase-catalyzed polyester synthesis (see cover story in Chemical & Engineering News, June 30, 2003) via condensation or ring-opening polymerization reactions.

Over the years, Prof. Gross have developed an expertise in enzyme catalyzed reactions such as step condensation and ring opening polymerizations for preparation of aliphatic polyesters. Used extensively in his research is a class of lipase B enzyme called Candida Antarctica (CALB) which is physically immobilized on a macroporous polymer material. Commercially, this enzyme is available as Novozym 435 from a Denmark-based biotech company Novozymes.

Starting materials for such synthesis are hydroxyl fatty acids, which can be derived from plant or animal sources (oils/fats). According to the research summary on Prof. Gross’s website, polyesters prepared by lipase-catalysis from long chain hydroxylfattyacids are strong-tough plastics that offer properties that are intermediate between poly(ε-caprolactone) and polyethylene. Although, not quite in the class of engineering plastics, these materials can still be expected to have moderately good physical properties for packaging applications. If unsaturated fatty acids are used, it is possible to introduce crosslinking in the resulting polyester, which can further improve the physical properties of these materials.

In packaging applications, these materials can be converted into a film or rigid containers depending on their physical properties. Typically, the packaging material is discarded right after the first use. Therefore, a lot of waste is generated from packaging materials. I was surprised to learn from the New York Times story that a soldier generates on average more than 7 lbs of packaging waste per day. That’s quite a lot!

This is where I am impressed by the value of Prof. Gross’s idea. If the packaging material is made from his biopolyester, the trash can be collected and converted into biodiesel using Cutinases, a class of enzymes that catalyze the hydrolysis of the ester bonds in cutin, a waxy lipid-polyester found in the plant cuticle. In this way, the long-chain biopolyester gradually breaks down into smaller alkyl-ester fragments, which at a certain point, separate out of the water mixture as biodiesel! Now it can be used to run diesel generators, for example, to make electricity.

What an excellent idea!

Carbon Nanotubes Still Not A Cheap Material

Stuart Cantrill’s post “A nanotube fix” on nature.com got me interested in looking up suppliers and prices of single-walled (SWNT) and multi-walled nanotubes (MWNT). He noticed an interesting comparison between cost of SWNT and another more interesting chemical on Wikipedia’s entry on carbon nanotubes:

Single-walled nanotubes are still very expensive to produce, around $1500 per gram as of 2000 (compared to marijuana, which generally costs between $10 and $30 per gram, depending on who you know and how sweet the nug is) ……

Although, the Wikipedia entry has been fixed, I was very amused by this comparison!

Anyway, here is what I found through various sources on the web:

• Cheap Tubes Inc (Vermont, USA): SWNT of high purity at $250/g. Appears that the price might be $75/g for a 1 KG order (check out the price list on the website). MWNT’s are much cheaper, around $0.18/g for an order of 1 ton of the industrial grade. Production capacity is 10 – 12 MT/year of MWNT and 1 Kg/month of SWNT.
• Nanothinx SA (Patras, Greece): High purity SWNT at 180 Euro/g and MWNT 10 -20 Euro/g (see price list). Still a low capacity player, although promises to be above 1 MT/year by end of 2007 through a new high-yield process.

Bayer Material Science (Germany): MWNT commercialized under the Baytube(R) brand. According to a February 2007 press release, current pilot plan capacity is 30 MT, however a large-scale plant with 3000 MT capacity is planned.

• Arkema (France): MWNT commercialized under the Graphistrength(TM) brand. Current pilot plant capacity reported to be around 10 MT. Recently announced a joint development deal with Zyvex to utilize their Kentera(TM) dispersion technology to develop various value-added MWNT systems for different applications. Also the sole supplier in Europe of Zyvex’s Nanosolve(R) product line.

Several other selected smaller players are emerging across the world:

• Ahwahnee Technology (USA): SWNT and MWNT
• BuckyUSA (USA): Fullerenes, SWNT ($250-750/g), MWNT ($100-150/g)
• Carbolex (USA): Lower purity SWNT ($50-100/g)
• Carbon Nanotechnologies Inc(USA): Buckytubes, Research grade SWNT ($375-2000/g)
• Carbon NT&F 21 (Austria): 5-10MT of SWNT and MWNT
• Iljin Nanotech (Korea): SWNT, MWNT
• Nanolab (USA): SWNT ($175-2000/g), MWNT ($2.5-700/g). Current capacity of 2MT going up to 20 MT by 2008-2009
• NTP (China): SWNT, MWNT

This is not meant to be the complete list. Nanotube-suppliers.com has many more listings. Similar to all new technologies, the industry is quite fragmented with a large number of suppliers. In time, this will surely lead to consolidation among these suppliers. Already, Cheap Tubes Inc. claims to have the following mission:

We are embracing the commodity status of Carbon Nanotubes. Many of our competitors are unwilling to accept that ultimately CNTs are a commodity. We believe that when a product is a commodity then if features and quality are equal, then price is largest governing factor. We are striving to be the highest volume, lowest cost CNT supplier.