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The electrical degradation in AlGaN/GaN high-electron-mobility transistors (HEMTs) is examined under irradiation with 7.6-MeV carbon (C), 20-MeV oxygen (O), and 30-MeV fluorine (F) ions in situ. To characterize the radiation damage in the HEMTs, the ionizing dose Di, displacement dose Dd, and number of vacancies versus the chip depth in the devices have been calculated for heavy ions. As expected, in all three types of HEMTs, the output current decreases more than 30% and threshold voltage positive shifts after the irradiation fluence of 4 × 1012 ions/cm2. The performance degradation of AlGaN/GaN HEMTs is caused by radiation-induced charged defects. Based on calculation and experimental results, it is shown that the nonionizing energy loss (NIEL) method is not suitable for estimating the degradation of AlGaN/GaN HEMTs either considering gallium vacancy or considering both gallium vacancy and nitrogen vacancy. In the same displacement damage dose, the threshold voltage degradation rate depends on the type of incident particles and independent of the channel length. The damage caused by carbon ions is the smallest and the damage caused by fluoride ions is the largest. [ABSTRACT FROM AUTHOR]

The evolution of ionizing radiation-induced defects in gated lateral p-n-p (GLPNP) bipolar transistors at different temperatures is investigated. The experimental results show that when the irradiation dose is less than 25 krad, the change in the reciprocal current gain (Δ (1/β)) increases by increasing the temperature gradually at a given dose. When the dose is more than 25 krad, Δ(1/β) increases first and then decreases at 200 °C by increasing the temperature at a given dose. Gate sweep (GS) technique and deep-level transient spectroscopy (DLTS) analyses show that the positive oxide trapped charges decrease by increasing the temperatures. When the temperature is less than 200 °C, the number of the interface traps gradually increases by increasing the temperature, but when the temperature increases to 200 °C, the number of the interface traps decreases. It indicates that the formation of the positive oxide trapped charges was inhibited at different temperatures above room temperature, and the formation of the interface traps was promoted at less than 200 °C and annealed significantly at 200 °C. Moreover, the change in the number of the interface traps in the transistors induced by the irradiation under different temperatures decides the degradation of the current gain. [ABSTRACT FROM AUTHOR]