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.

In this paper, the DC and RF characteristics of our own InP-based HEMTs were investigated comprehensively with surface traps concentration varying among 0 cm À2 , 1 Â 10 12 cm À2 , 3 Â 10 12 cm À2 . Reasonable physical models were used to describe the device performances, including hydrodynamic transport model, density gradient model, recombination models and so on. Moreover, surface Shockley-Read-Hall model and improved Possion's equation were introduced to implement for the impact of surface traps. The DC and RF characteristics have shown compatible trends between computation and experiment. With the increasing surface traps concentration over the gate-recess region, the channel current, transconductance, current gain cut-off frequency (f T ) and maximum oscillation frequency (f max ) exhibit apparent decrease trends. The observed obvious changes of the DC and RF properties with surface traps could be accounted for carrier sheet density reduction, which resulted from the surface potential modulated by negatively charged surface traps. Additionally, the charged surface traps could deplete the electrons in channel region, which leads to an increase in channel sheet resistance, and thus, further decreasing the f max .

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