The performance damage mechanism of InP-based high electron mobility transistors (HEMTs) after proton irradiation has been investigated comprehensively through induced defects. The effects of the defect type, defect energy level with respect to conduction band E T, and defect concentration on the transfer and output characteristics of the device are discussed based on hydrodynamic model and Shockley–Read–Hall recombination model. The results indicate that only acceptor-like defects have a significant influence on device operation. Meanwhile, as defect energy level E T shifts away from conduction band, the drain current decreases gradually and finally reaches a saturation value with E T above 0.5 eV. This can be attributed to the fact that at sufficient deep level, acceptor-type defects could not be ionized any more. Additionally, the drain current and transconductance degrade more severely with larger acceptor concentration. These changes of the electrical characteristics with proton radiation could be accounted for by the electron density reduction in the channel region from induced acceptor-like defects.
InP-based high electron mobility transistors (HEMTs) will be affected by protons from different directions in space radiation applications. The proton irradiation effects on InAlAs/InGaAs hetero-junction structures of InP-based HEMTs are studied at incident angles ranging from 0 to 89.9 • by SRIM software. With the increase of proton incident angle, the change trend of induced vacancy defects in the InAlAs/InGaAs hetero-junction region is consistent with the vacancy energy loss trend of incident protons. Namely, they both have shown an initial increase, followed by a decrease after incident angle has reached 30 • . Besides, the average range and ultimate stopping positions of incident protons shift gradually from buffer layer to hetero-junction region, and then go up to gate metal. Finally, the electrical characteristics of InP-based HEMTs are investigated after proton irradiation at different incident angles by Sentaurus-TCAD. The induced vacancy defects are considered self-consistently through solving Poisson's and current continuity equations. Consequently, the extrinsic transconductance, pinch-off voltage and channel current demonstrate the most serious degradation at the incident angle of 30 • , which can be accounted for the most severe carrier sheet density reduction under this condition.
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.
In this paper, an improved charge control model is proposed to investigate the effect of proton irradiation on InP‐based high electron mobility transistor (HEMT) with fluence varying among 0, 1 × 1011, 5 × 1011, 1 × 1012, and 2 × 1012 cm−2. The non‐uniform acceptor‐like defects in InAlAs/InGaAs hetero‐junction layers have been taken into account in the charge control model of the device after proton irradiation. The simulated characteristics by the charge control model have shown compatible trend with experimental data. The calculated results show that the channel current, transconductance, and current gain cutoff frequency depict a decline trend with the increase of proton fluence, and the pinch‐off voltage drifts toward positive value. Moreover, the performances gradually begin to degrade after the proton fluence reaches 5 × 1011 cm−2, and deteriorate dramatically with proton fluence up to 2 × 1012 cm−2. The observed obvious variation of electrical properties with different proton fluence could be accounted for by the carrier sheet density reduction, which is a result of the carrier removal effect from induced As acceptor‐like defects.
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