Effect of protons located at different region in SiO2 layer on GLPNP transistors degradation

Based on 100-keV, 130-keV and 170-keV proton irradiations, the contribution of ionization damage to the electrical property degradation of gate controlled lateral PNP (GLPNP) transistors is investigated. The key electrical parameters are measured in-situ during irradiations. The radiation-induced defects are characterized by deep level transient spectroscopy (DLTS). Experimental results show that the same ionization dose of various energy protons caused different degradation of current gain in GLPNP transistors. The current gain of the irradiated transistors by 170-keV protons degrades obviously, while that of the irradiated transistors by 100-keV protons does not almost change. As the ionization dose increases, the excess base currents of the irradiated transistors by 170-keV and 130-keV protons increase. The ideality factor of the irradiated transistor by 170-keV protons changes, while that of the transistor irradiated by 130-keV protons does not change. The gate sweep (GS) curves show that the main ionization defects induced by different protons are the interface traps. Compared with the irradiated transistors by 100-keV and 130-keV protons, the irradiated transistors by 170-keV protons has a high gate sweep peak at the same dose indicating that the 170-keV protons induced more interface traps. Therefore, the protons located at different region in SiO2 of GLPNP transistors can induce different degree of degradation, and the location of the proton is closer to the Si/SiO2 interface, the number of the radiation-induced interface traps is the more.