Diamond layers for active electronic devices

This paper reviews our recent achievements in homoepitaxial CVD diamond layers for electronic devices. We have successfully synthesized high quality homoepitaxial diamond layers with atomically flat surface by the microwave plasma chemical vapor deposition (CVD) using a low CH4 concentration of CH4/H2 gas system less than 0.15% CH4/H2 ratio and Ib (001) substrates with low-misorientation angle less than 1.5°. These layers have atomically flat and have excellent electrical and optical properties. For example, highquality Schottky junctions between Al and p-type high-conductivity layer near the surface of these layers have been obtained. Based on this growth method, we have also successfully synthesized B-doped diamond layers using trimethylboron [B(CH3)3,TMB] gas as a B doping source, whose Hall mobility is 1840 cm²/Vs at 290 K. Schottky junctions fabricated by the B-doped diamond also show excellent performances, indicating that the quality of these diamond layers is device grade.