High-temperature performance of AlGaN/GaN HFETs and MOSHFETs

Modeling the effect of thin gate insulators (SiO2, SiN, Al2O3 and HfO2) on AlGaN/GaN HEMT forward characteristics grown on Si, sapphire and SiC

“…In general, the electron mobility differences between identical HEMT and MIS-HEMTs are reported to be even smaller than for n s [26,27]. Donoval et al [34] have reported the same temperature dependence for I ds,sat and g m HEMT and MIS-HEMT as T À 1.5 , suggesting that phonon scattering is the predominant effect, regardless of the gate stack architecture. The hypothesis of the electron mobility conservation seems plausible.…”

“…However, in general, it may be observed that a relatively small increase or decrease ( $ 1-10%) of the 2DEG carrier concentration occurs due to the action of the passivation of surface charges, thereby affecting somehow the AlGaN polarization charge [28,29]. The variety of gate insulators and deposition techniques has resulted in a strong dispersion of the available data in the literature [26][27][28][29][30][31][32][33][34]. In this sense, it is worth mentioning that some authors have reported more relevant differences in n s and m n when comparing Schottky and MIS gate HEMTs [30,31].…”

Multilayer Pt/Al based ohmic contacts for AlGaN/GaN heterostructures stable up to 600°C ambient air

“…A temperature stable 2DEG in combination with a wide band gap enables AlGaN/GaN heterostructures to become an ideal technology platform for development of electronic devices for extreme environment applications. Different research groups have experimentally analyzed the material stability and electrical characteristics of AlGaN/GaN heterostructures up to 900°C [3][4][5][6][7][8][9] . It was observed that in-situ deposited SiN enables stability of GaN heterostructures up to 900°C 5-6 .…”

Thermoreflectance CCD imaging of self heating in AlGaN/GaN high electron mobility power transistors at high drain voltage

“…Other significant material advantages of GaN are its large bandgap of 3.4 eV, which permits high breakdown voltage due to a much higher electric field at which impact ionization becomes a limiting factor, and much lower intrinsic carrier concentrations allowing a maximum operating temperature of up to 970 K. [1] Thermal processes, however, remain a significant factor in performance and reliability of GaN based transistor devices. GaN HEMTs have shown saturation current dependence on temperature [2]. Due to the high power levels reachable in GaN HEMTs and the high electric fields achievable that can force this power to be dissipated in a small volume, temperature gradients can be extreme [3].…”