Low-Temperature Formation of SiO2 and High Dielectrics Constant Material for ULSI in 21st Century

Abstract

ABSTRACTA high-density plasma processing system featuring a radial line slot antenna has been developed for high-quality thin film formation at low temperature. This system is characterized by a high plasma density (above 1012 cm−3), a low electron temperature (below 1 eV) and a low plasma potential (less than 9 V). High-integrity silicon oxide films grown by direct oxidation of silicon surface at 400°C have been developed by introducing oxygen radical oxidation where oxygen radicals are obtained by a high-density plasma in He/O2 ambient. It is confirmed that the breakdown field intensity of oxide film is more than 15 MV/cm and the charge-to-breakdown is larger than 10 C/cm2under a constant stress current density of 0.1 A/cm2. The same high-density plasma system has also been applied for the direct nitridation of silicon surface using Ar/N2 or Ar/N,/H, gas ambient. The electrical properties of the silicon nitride are excellent enough to extend scaling limit of thermally grown silicon oxide. An advanced gas distribution system consisting of a newly-developed vaporizer, a flow control system, an electrically controlled valve and an advanced gas pumping system can control various source gas concentrations in the process chamber very accurately from the first atomic layer deposition. The newly-developed plasma and advanced gas distribution systems are suitable for the formation of high dielectric constant and ferroelectric films for ULSI in the 21st Century.