Microwave power and chamber pressure studies for single-crystalline diamond film growth using microwave plasma CVD

TL;DR

This study investigates how microwave power and chamber pressure affect the growth quality of single-crystalline diamond films via MPCVD, identifying optimal conditions for high purity and uniformity.

Contribution

It provides systematic insights into parameter effects on SCD film quality, enhancing process optimization for large-area diamond fabrication.

Findings

Optimal conditions: 3,900 W, 120 Torr yield high-quality films.

Films show low surface roughness (~2.0 nm) and high crystalline purity.

Uniform (100)-oriented single-crystal structure confirmed across samples.

Abstract

Single-crystalline diamond (SCD) films possess exceptional thermal, chemical, and optical properties, making them ideal for advanced applications. However, achieving uniform film quality via microwave plasma chemical vapor deposition (MPCVD) remains challenging due to spatial variations in plasma characteristics. This study systematically examines the influence of microwave power and chamber pressure on the growth of SCD films using CH4/H2 gas mixtures. Under optimized conditions (3,900 W, 120 Torr), the films exhibit low surface roughness (~2.0 nm), a sharp sp3 Raman peak at 1,332.2 cm-1, and no detectable C-H related features, indicating high crystalline purity. Cross-sectional TEM analysis confirms a uniform (100)-oriented single-crystal structure across the entire sample. These findings advance the understanding of the interplay between deposition parameters and film quality, and establish a more robust foundation for optimizing MPCVD processes in large-area, high-purity diamond fabrication.