AlGaN/GaN HEMTs passivated by Cat-CVD SiN Film

Non-polar (11-20) GaN grown on sapphire with double overgrowth on micro-rod/stripe templates

“…Furthermore, the sheet carrier density of a two dimensional electron gas formed at the interface between GaN and AlGaN depends sensitively on polarisation. As a result, any change in strain would also affect the electrical performance of such HFETs, potentially leading to performance degradation and reliability issues [10][11][12]. In order to address these challenges, a simple but promising solution is to grow an AlGaN/GaN heterostructure with modulation doping along a non-polar direction, where the polarisation can be eliminated and thus the sheet carrier density of 2DEG can be tuned simply through optimising the doping level in AlGaN barrie [9].…”

Surface protection mechanism of insulating films at junctions in compound semiconductor devices

“…To prove that the damage caused by PE-CVD and Cat-CVD is different, metal-insulator-semiconductor (MIS) diodes with an AlGaN (21 nm)/GaN epitaxial layer passivated by silicon nitride films (50 nm) that were deposited by either PE-CVD or Cat-CVD were prepared [2]. Stoichiometric Si 3 N 4 deposited by Cat-CVD and non-stoichiometric SiN x deposited by PE-CVD were used in our experiments.…”

“…Figure 1 shows the cross section of a compound semiconductor device that contains voids, grains, gap spaces and pin holes in the insulating film, and the external stresses like plasma damage, oxidation under a moist environment and junction degradation over an upper temperature limit. To prevent these external stresses from damaging device performance, a catalytic chemical vapor deposition (Cat-CVD) technique has been developed [1] and applied to AlGaN/GaN high electron mobility transistors (HEMTs) [2] and pseudomorphic HEMTs (pHEMTs) [3]. In this report, after reviewing examples of the application of silicon nitride films in semiconductor devices, a molecular orbital calculation is used to clarify the mechanism of moisture resistance of such films, which should aid their design.…”

Wide Band Gap Semiconductor Devices for Power Electronics

“…To efficiently operate the transistor at high frequency and high voltage, the drain current collapse must be suppressed and the gate-drain breakdown voltage must be improved. Several solutions for the device structure have been proposed including the surfacecharge-controlled n-GaN-cap structure, the recessed gate and field-modulating plate structure or the passivation of surface states via silicon nitride or other dielectric [31]. High voltage AlGaN/GaN HEMTs over 1 kV were reported in 2006 [32].…”