Free-standing Diamond Single Crystal Film for Electronics Applications

Abstract

AbstractHigh quality single crystal diamond film is an excellent transparent semiconductor material. Combined with its good electrical, optical, thermal and chemical properties, diamond-based semiconductor devices offer the potential of operation at very high voltages (>10 kV), power levels, and temperatures (>400°C) and under extreme radiation conditions.In this paper, we exploit the optical transparent property of MPCVD single crystal diamond films to correlate the quality of the epi-layers with the performance of Schottky barrier diodes fabricated on the layer. We used optical microscopy to observe stress induced birefringence caused by defects/dislocations in the material and micro- Raman/photoluminescence to detect relative amounts of non-diamond carbon and color centers (nitrogen and silicon atom complexes with lattice vacancies) in the material. High structural quality (low stress) is correlated with the properties of Schottky barrier diodes fabricated in the material. Vertical devices made from a 20 µm homo-epi-layer have been shown high breakdown fields of 1.85 MVcm-1 (BV = 3.7 kV) and conduction of 0.6 A/cm2 at 20V forward drop at 290 °C. Through device failure analysis, we can conclude that the 1.85 MVcm-1 field is only a lower limit for the material. Local stresses (dislocations) and point defects appear to be the main reasons for the high voltage failure of our single crystal diamond rectifiers.