Hydrogen in buried SiO2 layers

Mobile protons are generated at the buried oxide (BOX)/top-Si interface in Si/SiO2/Si structures by H atoms which permeate the top Si layer during hea t-treatment in H-2. About 1/1000 of the arriving protons form hydroxonium-l ike configurations with O atoms having a sufficient effective negative char ge, which are associated with "strained" Si-O bonds, and by transferring an electron from the H atom to the silicon. The strained bonds are generated thermally during the high temperature processing as the relaxation of the c onfined BOX is hindered and by compressive mechanical stress on the BOX, es pecially at the edges of the top Si layer. The interaction between protons and Si/SiO2 interfaces is limited or even nil from the standpoint of genera ting interface states. The probable reason is that the Si/SiO2 interfaces o f structures with a confined oxide layer (BOX) are different from those of conventional structures with unconfined oxide. (C) 2000 The Electrochemical Society. S0013-4651(00)03-092-5. All rights reserved.