High-mobility p-channel wide-bandgap transistors based on hydrogen-terminated diamond/hexagonal boron nitride heterostructures

Field-effect transistors made of wide-bandgap semiconductors can operate at high voltages, temperatures and frequencies with low energy losses, and are important for power and high-frequency electronics. However, wide-bandgap p-channel transistors perform poorly compared with n-channel ones, making complimentary circuits difficult to achieve. Hydrogen-terminated diamond is a potential p-type material for such devices, but surface transfer doping-thought to be required to generate conductivity-limits performance because it requires ionized surface acceptors that can lead to hole scattering. Here we show that p-channel wide-bandgap heterojunction field-effect transistors can be created, without surface transfer doping, using a hydrogen-terminated diamond channel and hexagonal boron nitride gate insulator. Despite having a reduced density of surface acceptors, the transistors have a low sheet resistance (1.4 k omega) and large ON current (1,600 mu m mA mm(-1)) compared with other p-channel wide-bandgap transistors, due to a high room-temperature Hall mobility (680 cm(2) V-1 s(-1)). The transistors also exhibit normally OFF behaviour with an ON/OFF ratio of 10(8). Wide-bandgap transistors with room-temperature hole mobility of 680 cm(2) V-1 s(-1) can be created without surface doping using hydrogen-terminated diamond/hexagonal boron nitride heterostructures.

Automated summary

This study demonstrates that wide-bandgap heterojunction field-effect transistors with a hydrogen-terminated diamond channel and hexagonal boron nitride gate insulator can be created without surface transfer doping. These transistors exhibit low sheet resistance, large ON current, high room-temperature Hall mobility, and normally OFF behavior with a high ON/OFF ratio.