Research Progress of Two-Dimensional Electrical Conductivity and Field Effect Transistors of Diamond
Diamond surface-channel field-effect transistor utilizes two-dimensional hole gas (2DHG) on the hydro-gen-terminated diamond surface as the channel to realize the control on output current by input voltage,and it is the main-stream structure of diamond electronic devices. The 2DHG conductivity has a large range of controllable sheet density and a high saturation drift velocity. This paper reviewed the research progress of diamond field-effect transistors in DC,frequen-cy,and power characteristics,and revealed that low mobility is the main limiting factor for the development of diamond-based low-power high-speed digital circuits,high-frequency devices,and high-power microwave devices. It summarized the theoretical and experimental research of a new doping mechanism similar to modulation doping that emerged for the dia-mond surface conductivity recently. At room temperature the 2DHG Hall mobility has increased to 680 cm2/Vs,and the rele-vant square resistance has decreased from about 10 kΩ/sq to 1.4 kΩ/sq,which is expected to cause a great improvement in the performance of diamond field-effect transistors.
Diamondhydrogen-terminatedfield-effect transistortwo-dimensional hole gas