High Voltage Diodes in Diamond Using (100)- and (111)- Substrates

We present a comparative study of PIN structures in diamond on type IIa (100)- and type IIb (111)-oriented bulk diamond substrates. An 8.5-μm thick i-layer demonstrated a blocking voltage>1kV for the (100)-oriented diamond sample without any mesa isolation, passivation, or edge termination structures. PIN diodes with a 530nm thick drift region, on the (111)-sample, demonstrated a blocking voltage of 207V at a current level of 1A/cm2with a corresponding blocking electric field of 3.9MV/cm. A deep ultraviolet light emission was observed only in (111)-diodes under forward bias, confirming well-behaved p-n junction characteristics in (111) as compared to (100).