Effect of Electron Irradiation Fluence on InP-Based High Electron Mobility Transistors.

In this paper, the effect of electron irradiation fluence on direct current (DC) and radio frequency (RF) of InP-based high electron mobility transistors (HEMTs) was investigated comprehensively. The devices were exposed to a 1 MeV electron beam with varied irradiation fluences from 1 × 10 cm, 1 × 10 cm, to 1 × 10 cm. Both the channel current and transconductance dramatically decreased as the irradiation fluence rose up to 1 × 10 cm, whereas the specific channel on-resistance (R) exhibited an apparent increasing trend. These changes could be responsible for the reduction of mobility in the channel by the irradiation-induced trap charges. However, the kink effect became weaker with the increase of the electron fluence. Additionally, the current gain cut-off frequency () and maximum oscillation frequency () demonstrated a slightly downward trend as the irradiation fluence rose up to 1 × 10 cm. The degradation of frequency properties was mainly due to the increase of gate-drain capacitance (C) and the ratio of gate-drain capacitance and gate-source capacitance (C/C). Moreover, the increase of may be another important factor for f reduction.