Evidence of space charge limited flow in the gate current of AlGaN/GaN high electron mobility transistors

Abstract

Room temperature gate leakage current measurements as a function of gate bias voltage are reported for different AlGaN/GaN high electron mobility transistors and interpreted in terms of space charge limited flow in the presence of shallow traps through very small area conductive leakage paths already present or formed under electrical stress in the gate stack device area. Transport parameters for electrons following these paths are extracted, and the observation of gate electron velocity saturation in stressed devices indicates that newly created leakage paths form predominantly in high electric field gate edge regions.

Self-assembled metal-oxo clusters for sensitive and low-powered ultraviolet photodetectors

“…In regime (II), the electron-trap density (n t ) values of ZOC and ZOC@PEI were estimated using eqn (5) were 1.51 × 10 12 cm −3 and 7.9 × 10 14 cm −3 , respectively. perovskites (such as Cs-FAPbI 3 , MAPbI 3 , FAMACs, and (FAPbI 3 ) 0.97 (MAPbBr 3 ) 0.03 ), 1,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] suggesting that the as-prepared ZOCs can serve as promising UV photoactive materials that exhibit both high UV selectivity and efficient photon-induced charge collection. Moreover, the trap density of ZOC@PEI was signicantly higher than that of ZOC, implying that the ZOC/PEI interfaces can act as electron-trapping sites.…”

“…3c compares the SCLC-derived trap density and bandgap values of the ZOCs and benchmark UV-sensitive materials. The trap densities of ZOCs are significantly lower than those of wide-bandgap metal oxides and metal nitrides (such as ZnO, Ga 2 O 3 , TiO 2 , and GaN) and comparable to those of organic/inorganic narrow-bandgap perovskites (such as Cs-FAPbI 3 , MAPbI 3 , FAMACs, and (FAPbI 3 ) 0.97 (MAPbBr 3 ) 0.03 ), 1,28–46 suggesting that the as-prepared ZOCs can serve as promising UV photoactive materials that exhibit both high UV selectivity and efficient photon-induced charge collection. Moreover, the trap density of ZOC@PEI was significantly higher than that of ZOC, implying that the ZOC/PEI interfaces can act as electron-trapping sites.…”

Mechanism and enhancement of the near-threshold low OFF-state breakdown voltage in gallium nitride high electron mobility transistors

“…12) Space charge effects in the presence of shallow traps in the AlGaN layer of an AlGaN/GaN HEMT were observed from gate leakage measurements. 13) Reference 14, modeled the surface leakage conduction in the gate-drain access region of a GaN HEMT using SCLC. Vertical breakdown due to SCLC was reported in a C-doped GaN buffer in two-terminal GaN diodes.…”

“…Prior works published in the literature have established an SCLC path between the gate and bulk in devices with Si substrates, 17) and between the gate and drain 13,14) independent of the substrate in AlGaN/GaN HEMTs. A report 18) suggesting the possibility of SCLC from drain to source in AlGaN/GaN HEMTs lacked direct concrete evidence.…”

Studies of traps in AlGaN/GaN high electron mobility transistors on silicon

“…High gate-leakage currents results in the device BVGD reduction, power-added efficiency reduction and also increases the noise figure [68]. Various gateleakage mechanisms have been proposed such as thermionic emission [69,70], thermionic field emission [71,72], trap assisted tunnelling [70,73], dislocation assisted tunnelling [74,75], defect hoping [73,76], Fowler-Nordhein tunnelling [77], Frenkel-Poole emission [78,79] and space charged limited current [80,81].…”