AlGaN/GaN on SiC Devices without a GaN Buffer Layer: Electrical and Noise Characteristics

Abstract

We report on the high-voltage, noise, and radio frequency (RF) performances of aluminium gallium nitride/gallium nitride (AlGaN/GaN) on silicon carbide (SiC) devices without any GaN buffer. Such a GaN–SiC hybrid material was developed in order to improve thermal management and to reduce trapping effects. Fabricated Schottky barrier diodes (SBDs) demonstrated an ideality factor n at approximately 1.7 and breakdown voltages (fields) up to 780 V (approximately 0.8 MV/cm). Hall measurements revealed a thermally stable electron density at N2DEG = 1 × 1013 cm−2 of two-dimensional electron gas in the range of 77–300 K, with mobilities μ = 1.7 × 103 cm2/V∙s and μ = 1.0 × 104 cm2/V∙s at 300 K and 77 K, respectively. The maximum drain current and the transconductance were demonstrated to be as high as 0.5 A/mm and 150 mS/mm, respectively, for the transistors with gate length LG = 5 μm. Low-frequency noise measurements demonstrated an effective trap density below 1019 cm−3 eV−1. RF analysis revealed fT and fmax values up to 1.3 GHz and 6.7 GHz, respectively, demonstrating figures of merit fT × LG up to 6.7 GHz × µm. These data further confirm the high potential of a GaN–SiC hybrid material for the development of thin high electron mobility transistors (HEMTs) and SBDs with improved thermal stability for high-frequency and high-power applications.

Roadmap of Terahertz Imaging 2021

“…The identification of CMOS technology as a promising platform for the development of THz devices [168] suggested different ways to make THz chips, as well as Schottky diodes [169], enabling reliable and circuits-friendly solutions. Concerning materials choice, GaAs [170] and GaN-based structures [171] remain as the main platforms for sensor development. These materials successfully served for the fabrication of nanodiodes for THz detection: GaAs-based devices, for instance, were able to reach 1.5 THz with 300 V/W sensitivity at room temperature [172], while equivalent values in operational bandwidth and sensitivity values for GaN nanodiodes were found to be of 200 GHz and 50 V/W, respectively [173,174].…”

Double-Quantum-Well AlGaN/GaN Field Effect Transistors with Top and Back Gates: Electrical and Noise Characteristics

“…The effect of the access resistance can be taken into account using the input gate voltage S for the trap density calculation [ 35 ]: We found N = (2–5) × 10 eV cm . Although smaller values of the trap density were reported in a few publications [ 40 , 41 ], the majority of papers reported the trap density to be within the same range or higher [ 35 , 36 , 42 , 43 , 44 ].…”

Development of Quaternary InAlGaN Barrier Layer for High Electron Mobility Transistor Structures

“…Furthermore, test devices were left with an unpassivated nitride surface. More details about the device processing have been reported elsewhere [ 12 , 27 ].…”

“…Currently, III-nitride high electron mobility transistor (HEMT) structures based on the AlGaN/GaN heterostructure are extensively used in various applications such as gas sensors [ 1 , 2 ], THz detectors [ 3 , 4 , 5 , 6 ] and emitters [ 7 , 8 ], and high-power microwave devices [ 9 , 10 , 11 , 12 ]. A combination of InN and AlN alloys with very different bandgaps, lattice and spontaneous polarization constants can be used to implement a wide range of electric and optic properties in the heterostructure [ 13 , 14 , 15 ].…”