Saturation drift velocity measurement for CVD diamond by combination of a charge distribution measurement and a TOF method using a UV pulsed laser

Drift velocities of charge carriers in polycrystalline diamonds were measured by a self-triggered time-of-flight (TOF) method with alpha particles based on a radiation measurement technique. Based on these measured results, a synthesis method for polycrystalline diamond was verified, and the electric properties of polycrystalline diamonds were improved; drift velocity was increased from 5 × 102 to 3 × 104 cm/s. The mean free paths (MFPs) of capture of charge carriers in a CVD single crystal diamond was obtained by induced charge distribution measurements with alpha particles, and drift velocity was measured by another TOF method using a UV pulsed laser. MFPs of capture of electron and hole in a CVD single crystal diamond were determined to be 5.4 and 9.6 μm, respectively; the hole and electron drift velocities were 5 × 105 cm/s and 3 × 105 cm/s in an electric field of 24.4 kV/cm, respectively. For diamond, short transit times of several nanoseconds and short MFPs of capture in several micrometers were successfully obtained for the first time by combining of these methods.