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Technology Stocks : Kopin Corp. (KOPN) -- Ignore unavailable to you. Want to Upgrade?

To: kech who wrote (577)	3/14/1999 2:59:00 PM
From: kinkblot	Read Replies (2) \| Respond to of 1820

Tom, here is a brief historical review of the connection, TTBOMK. When Kopin was first formed by Fan and others from the Electronic Materials Group at Lincoln Lab, the emphasis was on silicon-on-insulator layers and transference methods for those layers. If you look at their early display patents, you will see references to a method called 'CLEFT'. CLEFT = Cleavage of Laterally grown Epitaxial Films for Transfer I believe that many of the patents licensed from M.I.T. relate to this. For example, US Patent #4,727,047 "Method of producing sheets of crystalline material" (1988), which is referred to in Kopin's US Patent #5,206,749 "Liquid crystal display having essentially single crystal transistors pixels and driving circuits" (1993). Some of this may now be of historical interest only, since other transference techniques beyond CLEFT have been developed for the CyberDisplay. Besides the cleaving step, another critical part of the CLEFT procedure was the lateral growth of thin single-crystal semiconductor layers using a process called Zone Melt Recrystallization (ZMR). This was explored for both Si and GaAs. Wrt GaAs, I believe they initially looked at doing it on Si; see US Patent #4,826,784 "Selective OMCVD growth of compound semiconductor materials on silicon". Subsequently, Kopin developed a great deal of expertise in techniques for growing (esp. OMCVD) and thermally processing epitaxial layers of single and compound semiconductors. One outgrowth of this was their development of a carbon doping process, which is an important technology for their HBTs. They decided to build on that technical advantage and run with it. The HBT wafers made for Conexant's wireless handset chips include stacks of ~8 compound semiconductor layers on a GaAs substrate. These layers are done by epitaxy and each layer must have strictly controlled composition, doping and in some cases, grading. This sort of know-how would likely be kept proprietary and would not show up at the Patent Office. WT

To: kech who wrote (577)	3/14/1999 5:35:00 PM
From: kinkblot	Respond to of 1820

The GaAs on Si process I referred to was for monolithic integration, not cleft. I wasn't clear about that in the previous post. GaAs clefting or lift-off would be of a GaAs-on-insulator layer from a GaAs or Ge substrate. This would not be considered for transparent displays, but might someday be used for such things as an optical layer in a three dimensional processor: ---> US Patent #5,656,548 "Method for forming three dimensional processor using transferred thin film circuits", issued August 12, 1997, assigned to Kopin. See also the DARPA-funded "3D OptoElectronic Stacked Processor Consortium": soliton.ucsd.edu Honeywell is contributing their Vertical Cavity Surface Emitting Laser (VCSEL) expertise to the project. It's a long way from becoming reality, though. Another potential application would be LED arrays: ---> US Patent #5,300,788 "Light emitting diode bars and arrays and method of making same" covers LED elements and a method of forming them by transferring thin film III-V semiconductor layers. This is all peripheral to Kopin's main focus at the moment.