Process Variable Dependence and Interrelationship between Avalanche Charge Injection and Radiation Induced Carrier Trapping in Thermal Oxides.

摘要

The primary objective of this program is the investigation of the effects of processing variables on the trapping characteristics of injected charge carriers in thermal silicon dioxide. In addition, the nature and process dependence of avalanche injected trapped charges will be compared to those produced by ionizing radiation in identical oxides. The results obtained from this program should help in the determination of optimum process conditions for minimizing hot carrier trapping in VLSI device structures and in the establishment of accelerated test procedures for the evaluation of radiation trapping properties of thermal oxides. Characterization of the process dependence of avalanche injected electrons and holes in thermally grown silicon dioxide has been carried out. Process parameters investigated include oxidation temperature (800, 900, 1000, and 1100 C) oxidation ambient (02, H20 and 02/HC1); oxidation pressure (1,5 and 10 atm), post-oxidation insitu anneal ambient (N2, Ar), cooling ambient (02, N2, Ar, and H20), cooling rates (3 sec, 2 min, and 10 min), pre-metallization anneal in hydrogen, post-metallization anneal ambients (N2,H2, N2/H2), substrate orientation (100) and (111)), oxide thickness, polycrystalline silicon field plate deposition and process related radiation exposure (election beam, laser beam, and ion implantation). Results indicate basic differences between the process dependence of electron traps and that of hole traps.