High growth rate deposition of highly oriented polycrystalline diamond film

Abstract

(100) oriented polycrystalline diamond films are of benefit to applications such as optical windows and coatings due to its smoother as-grown surface and potentially better optical performance than randomly oriented diamond films. (100) Highly Oriented Diamond (HOD) films have been successfully grown on polished silicon wafer using the plasmaenhanced chemical vapor deposition technique (PECVD). The seeding procedure was based on Bias Enhanced Nucleation (BEN), which provided a high-density and uniform diamond nucleation on the entire two inch diameter silicon wafer. During the diamond deposition step subsequent to the BEN process, nitrogen gas was added in the standard methane/hydrogen processing gas mixture. The addition of small amount of nitrogen has three effects: 1) It increases the growth rate almost 3 times. 2) It stabilizes and enhances the (100) orientation growth. 3) It makes the HOD growth possible at high pressures (over 100 Torr) and high temperatures (over 1300 K). The diamond film has been characterized by confocal Raman and SEM, and an optimal temperature window for HOD growth has been identified. The growth rate of the (100) HOD growth rate reached > 16 μm/hour.