High breakdown voltage Schottky diodes synthesized on p-type CVD diamond layer

摘要

Diamond is a very promising material for power electronics and electrical energy management devices. Several architectures have been implemented in the past for the fabrication of Schottky diodes on boron doped microwave plasma enhanced chemical vapour deposition (MPCVD) layers and on lowly and highly boron doped stacked structures. Meanwhile, the performances often suffered several limitations, mainly due to insufficient crystalline quality of the layers or a non-optimized diamond/metal interface. In this study, we will especially show that the achievement of diamond Schottky diode with high breakdown reverse voltage and high breakdown field goes through the optimization of several factors: a net acceptor concentration below 10~(16) cm~(-3), the epilayer growth conditions, the implementation of efficient surface passivation techniques and the integrity of the metal/diamond interface. Optimizing the previous conditions enabled us to fabricate a lateral gold Schottky diodes withdrawing reverse voltages up to 7.5 kV before avalanche breakdown induced by an electric field in the range 7-9.5 MV/cm. These findings open the route for unipolar diamond devices operating in high power electronics without the use of guard rings or edge terminations contrary to other wide band gap semiconductors.