Effects of Si δ-Doping Condition and Growth Interruption on Electrical Properties of InP-Based High Electron Mobility Transistor Structures **Supported by the National Natural Science Foundation of China under Grant No 61434006.

Abstract

The InGaAs/InAlAs/InP high electron mobility transistor (HEMT) structures with lattice-matched and pseudomorphic channels are grown by gas source molecular beam epitaxy. Effects of Si δ-doping condition and growth interruption on the electrical properties are investigated by changing the Si-cell temperature, doping time and growth process. It is found that the optimal Si δ-doping concentration (Nd) is about 5.0 × 1012 cm−2 and the use of growth interruption has a dramatic effect on the improvement of electrical properties. The material structure and crystal interface are analyzed by secondary ion mass spectroscopy and high resolution transmission electron microscopy. An InGaAs/InAlAs/InP HEMT device with a gate length of 100 nm is fabricated. The device presents good pinch-off characteristics and the kink-effect of the device is trifling. In addition, the device exhibits fT = 249 GHz and fmax > 400 GHz.