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

Abstract

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 × 1014 cm−2, 1 × 1015 cm−2, to 1 × 1016 cm−2. Both the channel current and transconductance dramatically decreased as the irradiation fluence rose up to 1 × 1016 cm−2, whereas the specific channel on-resistance (Ron) 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 (fT) and maximum oscillation frequency (fmax) demonstrated a slightly downward trend as the irradiation fluence rose up to 1 × 1016 cm−2. The degradation of frequency properties was mainly due to the increase of gate-drain capacitance (CGD) and the ratio of gate-drain capacitance and gate-source capacitance (CGD/CGS). Moreover, the increase of Ron may be another important factor for fmax reduction.

Untitled

“…The defects induced by electron irradiation in the hetero-junction region degenerated the electron density and mobility through the carrier removal effect and scattering effect and led to the degeneration of output and transfer characteristics of device. To understand the irradiation-induced charged defects on the electron density and mobility, the electron density and mobility were calculated by [19][20][21]:…”

“…After electron irradiation, both f T and f max demonstrated a downward trend. The defects induced by electron irradiation increased the gate-drain capacitance and the specific channel on-resistance and led to the degeneration of f T and f max [20]. For device with 40 µm gate width, the f T was decreased from 153.0 GHz to 122.7 GHz and f max was decreased from 208.5 GHz to 185.7 GHz.…”

Degradation mechanisms of InP-based high-electron-mobility transistors under 1 MeV electron irradiation

“…Therefore, the degradation of RF characteristics was mainly due to the increase of C GD and C GD /C GS . In addition, electron irradiation significantly reduces carrier concentration in channel and results in an increase of R on [31], which may be another important factor for f max reduction.…”

Electron radiation impact on the kink effect in S 22 of InP-based high electron mobility transistors

“…Ohyama et al investigated the effect of high-energy particle radiation on AlGaAs/GaAs HEMTs, which revealed that the channel current and electron mobility were decreased with incident particle fluence [11]. Liu et al conducted a systematic study of proton radiation in AlGaN/GaN HEMTs, which indicated that the DC characteristics deteriorate more severely under high-fluence radiation [12]. As for InP-based HEMTs, our preliminary reports demonstrated that the channel current and frequency characteristics declined more and more seriously with the increase of both proton and electron fluence [13,14].…”