The following are a series of frequently asked questions about the Natcore liquid phase deposition process. We’ve found that the answers to these questions help to explain what the Natcore process is, and what it is not. Q. Is this a sol-gel process? A. No, this is not a sol-gel process. Natcore’s process is a development of a process called liquid phase deposition (LPD). Q. How does Natcore’s process differ from a sol-gel process? A. The sol-gel process requires the reaction of an organic-containing precursor that results in the incorporation of impurities into the sol-gel formed material. These impurities must be removed by pyrolysis. In contrast, Natcore’s process uses no organic compounds and, therefore, the associated impurities cannot be incorporated. Q. Has LPD been used before? A. Yes, successfully by a number of research groups. However, unlike prior research in this area, Natcore’s patent-applied for and proprietary technology allows for faster growth rates to be maintained over a long reaction time. Q. Is purity of the film the only difference between sol-gel and Natcore’s process? A. No, the sol-gel process results in homogeneous nucleation, causing solids to form within the solution instead of on the desired surface. These particles formed in solution then drop onto the surface being coated, causing defects. In contrast, Natcore’s process is shown to react by heterogeneous nucleation at the interface between the growth surface and the reagent solution. Therefore, Natcore’s process grows a film at the surface, where the film is required. Q. Is this is a slow process? A. Traditional liquid methods give fast film growth initially, but the rate of growth then slows. In contrast, Natcore’s technology allow for faster growth rates to be maintained over a long reaction time. Q. What are your competitive advantages over other processes? A. The technical advantages of Natcore’s process in comparison with other solution methods (such as sol-gel) are higher purity, greater film uniformity and deposition rate. The advantages of Natcore’s process in comparison with vapor methods (such as high temperature oxidation) include the use of a lower-energy process, the use of well established methods, and the use of low-cost equipment that is typical of a semiconductor device FAB facility. Q. Does that relate to a commercial advantage? A. Yes, Natcore believes that our initial competitive advantage will be sharply reduced costs and dramatically increased throughput for oxide film growth. Q. Will this need a large financial commitment for implementation? A. No, the chemicals used in Natcore’s process are all typically found in a FAB facility and are readily purchased in high purity. The equipment that will be used for Natcore’s process is the same as that used in all FAB facilities in the world for cleaning and etching silicon wafers. Q. Isn’t the silicon-on-insulator (SOI) process a multi-step and very complex technology? Does any one step really make an impact? A. Yes, there are many steps. However, the SOI wafer producers are searching for any and all cost-reduction techniques and technologies since their competition is so great. Q. Is Natcore’s process limited to coating silicon wafers? A. No, part of Natcore’s process is the ability to deposit a coating on a range of metal substrates. Among potential applications, this enables is the formation of circuits of optical interconnects on computer circuit boards using their present metal interconnects as guides. Q. Is the technology protected by patents? A. Yes, Natcore has an exclusive license from Rice University for the technology. Q. What degree of coverage does the Patent have? A. The patent has been granted in Russia and is pending in the U.S., Europe and other countries. Natcore has performed extensive patent and literature searches and believes that our patents will be issued. Q. Are there any applications not covered by our agreement with Rice? A. Natcore has certain proprietary technology that it intends to file in the U.S., Europe and other countries. At present this proprietary technology has either been filed as provisional patent applications or is being kept as trade secrets. The rights to this additional technology are exclusively owned by Natcore. Q. Everything in the current state of the art argues against your claims. Experience shows that greater heat and more extreme pressure differentials yield progressively better oxide films. How can you make such a claim that flies in the face of all previous experience? A. Yes, this process is opposed to current high-energy consumption methods. And that’s precisely why it is such a compelling technology, and has such important implications going forward. Natcore has taken an approach similar to nature. Man-made materials (oxide formed by high temperature oxidation) are formed under extreme conditions. In contrast, nature uses low-energy-designed pathways to make materials with high purity. Q. So it’s a new approach, but isn’t it just a curiosity from a professor’s laboratory? A. While Natcore’s process was originally developed in Professor Barron’s laboratory within the Center for Nanoscale Science and Technology at Rice University, Natcore has put the process through rigorous, independent testing by a globally respected laboratory. Q. What are the results of these independent tests? A. One of the world’s most respected laboratories was able to scale up the process as developed by Professor Barron and uniformly coat multiple wafers in a single reaction bath. They were able to quickly replicate Professor Barron’s results and improve the scale and film purity. The films have passed all tests with flying colors, including analyses of uniformity, growth rates, conductivity, reproducibility and early-stage testing for purity. Q. Have additional tests been performed? A. Yes, two additional independent labs have been used for confirmation of the film purity. |