Low-Compensated Boron-Doped Homoepitaxial Diamond Films Using Trimethylboron

We have grown low-compensation-controlled boron (B)-doped homoepitaxial diamond films with trimethylboron B(CH3)3 gas as a B doping source using microwave plasma chemical vapor deposition (CVD). This study was based on the approach that the synthesis of device-quality films was performed in a clean CVD system with the ability of precise growth condition control. Hall-effect measurements showed that the highest values of Hall mobility in the B-doped films were 1840 cm2/Vs at room temperature (290 K), when the hole concentration was 2 × 1014 cm—3, and 3370 cm2/Vs at 170 K. The donor (compensation) concentration and the compensation ratio of this film were (4 ± 1) × 1014 cm—3 and about 0.4%, respectively. Both values are the lowest ones of B-doped diamonds, including natural IIb ones, reported till now. Furthermore, high-quality Schottky junctions have been obtained by using our B-doped diamond films. These results indicate that the present B-doped CVD films are semiconducting device-grade.