Electrical characterization of interfacial reactions in ultrathin oxides during postmetalization anneal

The chemical reduction of ultrathin oxides in aluminum-SiO2-silicon metal o xide semiconductor (MOS) structures during post-metalization anneal was Stu died by means of electrical measurements. This reduction is a possible way of increasing the capacitance of the MOS device without necessarily increas ing the leakage current and also without harming the electrical Si-SiO2 int erface. This is accomplished by replacing part of the SiO2 with a compound of higher permittivity. The reduction was found to be insensitive to (i) th e substrate doping type, (ii) the oxidation ambient, (iii) the oxidation te mperature, and (iv) the initial oxide thickness. It appears to be dependent on the oxide quality. An accurate method of determining the thickness diff erence between two dielectrics using capacitance-voltage measurements is al so presented. (C) 1999 The Electrochemical Society. S0013-4651(98)11-045-5. All rights reserved.