Research On Ionization-induced Defects Of Gated Lateral Bipolartransistor In Hydrogen Ambient

The effect of hydrogen on ionization damage caused by 1 Me V high-energy electrons and 70 ke V low-energy electrons is examined for gated-controlled lateral PNP(GLPNP) transistor soaked in the hydrogen. Electrical parameters of GLPNP transistor are measured in-situ using a semiconductor characterization system, combined with gate sweep(GS) technology, sub-threshold sweep(SS) technology, deep level transient spectra(DLTS) and isothermal annealing. Based on the above analysis, the effect of hydrogen on ionization damage and annealing effect of GLPNP transistor is revealed.Experimental results show that, the degradation law of GLPNP transistor exposured to 1 Me V electrons and the 70 ke V electrons is similar. The irradiated GLPNP transistor by 1Me V and 70 ke V electrons soaked in the hydrogen environment prior to radiation exposure suffers from severe degradation of current gain. Based on the GS, SS and DLTS analysis, it can be shown that GLPNP transistor soaked in the hydrogen produces more damage defects caused by 1 Me V and 70 ke V electrons, indicating that molecular hydrogen can promote th formation of radiaton-induced interface trap and oxide-trapped-charge buildup in bipolar oxides during 1Me V and 70 ke V electron irradiation.Under the same ionization absorbed dose, compared with the 70 ke V electrons, the 1Me V electrons can cause more degradation on GLPNP transistor, forming more interface trap and oxide-trapped-charge. Through the analysis of the relation between minority carrier lifetime and oxide trapped charge and interface traps, it ca n be shown that ionizing damage defects causing by 1 Me V electrons could reduce the minority carrier lifetime of emitter junction and neutral base region, causing the increase of recombination current of GLPNP transistor. There are two reason for the decrease of the minority carrier lifetime. On the one hand, oxide trap charges accumulate in the surface of emitter junction, making the space charge move to the emitter depletion region. On the other hand, the number of interface traps increases induced by irradiation.In isothermal(150℃) annealing experiment, hydrogen obviously influences radiaton-induced interface trap and oxide-trapped-charge in the GLPNP transistor during annealing. Hydrogen could promote the recovery of oxide trapped charge and interface traps in the GLPNP transistor induced by 1Me V and 70 ke V electron irradiation, which accelerates the recovery degree of current gain of GLPNP transistor.