Experimental Demonstration of n- and p-channel GaN-MOSFETs toward Power IC Applications

We report on the systematic demonstrations of the depletion-mode p-channel and enhancement-mode n-channel GaN metal-oxide field-effect transistors (MOSFETs) based on homoepitaxial p-GaN substrates. The world's first depletion-mode p-channel GaN-MOSFET fabricated in this work shows a good Ion/Ioff characteristic (∼104) and an effective channel hole mobility of approximately 0.2 cm2/V·s at room temperature. For the first time, it is proved that the p-channel GaN-MOSFETs can work independently without the necessity of two-dimension hole gas (2DHG) sources of heterostructures. Meanwhile, the maximum effective electron mobility of n-channel GaN-MOSFETs is approximately 105 cm2/V·s. The post deposition annealing (PDA) treatment of Al2O3 dielectrics is also verified in both n and p-channel GaN-MOSFETs and 700°C is found to be the optimized condition on improving the effective hole/electron mobility. The findings in this work provide a valuable information in the design of novel power electronics taking advantage of p-type doped GaN.