High rate growth and electrical/optical properties of high-quality homoepitaxial diamond (100) films

Undoped and boron doped homoepitaxial diamond films were grown by high-power microwave plasma chemical vapor deposition (MPCVD). Growth rate was 2.5 μm/h under optimized growth conditions. The grown undoped film thus grown showed large diffusion length of 10.2 μm while short lifetime of 15 ns for electron. The growth rate increased up to 25 μm/h with increasing methane concentration, while free-exciton recombination emission was observed at room temperature. We found the surface became smooth and growth rate increased with increasing substrate temperature. Hall measurement for boron-doped sample revealed high hole mobility of 1500 cm2/Vs at 290 K for relatively high acceptor density of 1.4×1018 cm-3. The high-power MPCVD is, thus, indispensable for high-rate growth of diamond films for electronic devices.