The following sources and references cited should be useful: 1. Sorab K. Ghandhi, "VLSI Fabrication Principles - Silicon and Gallium Arsenide," John Wiley and Sons, NY, 1983, pp. 488-490. (I believe their is also a second edition of this text). 2. S.M. Sze (editor), "Semiconductor Sensors," John Wiley and Sons, NY, 1994, pp. 42-50. 3. W.R. Runyan and K.E. Bean, "Semiconductor Integrated Circuit Processing Technology," Addison-Wesley Publishing Company, Reading, MA, 1990, pp. 252-258 (especially Table 6.1 on p. 257). Best regards, Ed Kolesar W.A. Moncrief Professor of Engineering Texas Christian University Department of Engineering Fort Worth, TX 76129 Telephone: (817) 921-7677 or -7126 Telefax: (817) 921-7136 or -7704