(Invited) Scaling Requires Continuous Innovation in Thermal Processing: Low-Temperature Plasma Oxidation

Abstract

The required temperature in semiconductor process technology is going in two extreme directions. Either very high temperatures (up to 1300°C) with very short durations on the order of milliseconds are required for highest dopant activation, or extremely low temperatures are needed for forming high-quality dielectrics with minimum dopant deactivation and redistribution. This contribution describes a new microwave plasma oxidation apparatus with unique features addressing the before-mentioned low-temperature process requirements. With this new technique the oxide growth rate was studied as a function of time, gas ambient, pressure, applied microwave power and silicon substrate parameters to determine crystallographic oxidation rate anisotropy and dopant concentration independent oxidation at temperatures well below 500°C. The "More-Moore" approach of geometrical scaling in 2D will soon come to a physical end and therefore new requirements related to the thermal budget occur. Additionally, the transition from 2D- to 3D-devices requires extremely conformal oxide growth. Both the low temperature and the conformal oxide growth will be demonstrated on test structures.