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Technology Stocks : Advanced Micro Devices - Moderated (AMD) -- Ignore unavailable to you. Want to Upgrade?

To: Pravin Kamdar who wrote (21718)	12/6/2000 5:35:03 PM
From: THE WATSONYOUTH	Read Replies (1) \| Respond to of 275872

Perhaps you can give us all a summary. However it is currently being done, it should not preclude them from using Si28. The two main techniques are too complex for me to describe well here. I refer you to the Mass. company IBIS for a more complete description of oxygen implantation (SIMOX) techniques and to the french company SOITEC for an explanation of their remarkably clever "smart cut" approach to wafer bonding. I would guess AMD would use one of these two techniques. Obviously, if they are in the process of installing high current oxygen implanters, they are going with the SIMOX approach. I sincerely doubt they will use the approach you described. Microprocessors currently being manufactured in bulk silicon use several microns of P- epi on P+ substrates. Yes, the P- epi could just as well (and probably as easily) be grown from Si28 sources. (SiCl4/SiHCL3/etc.) On SOI substrates, it is not clear that P-epi on P+ substrates is any longer needed. Also, the buried oxide in most current SOI approaches is approximately equal in thickness (100nm to 200nm) to the thickness of the active silicon islands in which the devices are formed. Under these conditions, there is a considerable silicon "self heating" effect observed. In pulsed AC mode, on currents are measured for single typical SOI devices. When these same on currents are measured under DC conditions, they typically degrade 5%-6%. This is due to the self heating. I believe it is generally assumed that for all reasonable duty cycles and device layouts, this self heating effect is not of any consequence. But, I'm not a device guy. I am dubious of this whole Si28 stuff. But, I'm not a materials guy either. I'll track down the right people and will get back to you. My interest is piqued also. ibis.com soitec.com THE WATSONYOUTH