Highly-reliable ultra-thin oxide formation using hydrogen-radical-balanced steam oxidation technology

Abstract

A new oxide formation technology featuring oxidation in a strongly reductive ambient followed by an Ar gas annealing has been developed. We call this oxidation method H/sup */-H/sub 2/O oxidation. In this oxidation process, only the strong Si-O bond which is perfectly resistant even to the strongly reductive ambient survives and a high integrity oxide film can be grown. From the results of the breakdown tests by stepped voltage (E/sub BD/) and constant current stress (Q/sub BD/), the gate voltage shift (Vg shift) measurement under constant current stress, and the stress induced leakage current test, it has been revealed that the thin oxide film featuring high-integrity in breakdown and strong immunity from electrical stress is obtained by H/sup */-H/sub 2/O oxidation with post-oxidation-annealing in Ar ambient. This oxidation method is effective to form the thin oxide used under high electric field condition such as a tunnel oxide for flash memories.<>