METHOD OF OXIDIZING SILICON NITRIDE MATERIALS AT LOW THERMAL BUDGETS.

摘要

A method of forming silicon oxide by thermal oxidation of silicon nitride (or similar such material like silicon oxynitride) is disclosed. The method entails the use of low energy siliscon ion implantation for introducing Si ions in the nitride layer, such that a thermal silicon oxide can be formed over a nitride layer under steam or dry oxidation conditions using a conventional furnace under atmospheric pressure without the need of high thermal budgets. Apllication of the claimed method to thefabrication of an oxide-nitride-oxide (ONO) dielectric stack of a SONOS type memory dvice is also disclosed. The method may include the steps of forming a dielectric layer over a semiconductor substrate, forming a nitride layer, implanting silsicon ions at low energy levels (preferably between 0.5 keV and 5keV), forming a thermal top oxide at low thermal budgets (preferably in the range of about 700-950 degrees Celcium for about 5 to 60min) under oxidizing ambient in a conventional atmospheric furnace.