Vertical stack reliability of GaN-on-Si buffers for low-voltage applications

In this paper the reliability of the vertical GaN-on-Si stack for lateral p-GaN HEMTs dedicated to low-voltage applications is discussed in detail by comparing wafers with different buffer thicknesses and growth condition of the AlN nucleation layer. The vertical robustness and the time-dependent vertical breakdown will be investigated in detail, demonstrating that the buffers with reduced thickness are suitable for 100 V applications. Moreover, the voltage drop on the different layers of the vertical stack will be extracted at the breakdown, and a model able to explain the degradation of the vertical stack will be proposed.