Characteristics of transport properties in ultra-wide bandgap Al0.65Ga0.35N channel HEMTs with low contact resistance and high breakdown voltage (>2.5 kV)
Abstract
Ultra-wide bandgap (UWBG) Al0.65Ga0.35N channel high electron mobility transistors (HEMTs) were deposited using a close-coupled showerhead metal-organic chemical vapor deposition reactor on AlN-on-sapphire templates to investigate the effect of transport properties of the two-dimensional electron gas (2DEG) on the epitaxial structure design. The impact of various scattering phenomena on AlGaN channel HEMTs was analyzed with respect to the channel, buffer, and AlN interlayer design, revealing that the alloy disorder and ionized impurity scattering mechanisms were predominant, limiting the mobility of 2DEG up to 180 cm2/Vs for a sheet charge density of 1.1 × 1013 cm−2. A surface roughness of <1 nm (2 μm × 2 μm atomic force microscopy scan) was achieved for the epitaxial structures demonstrating superior crystalline quality. The fabricated HEMT device showed state-of-the-art contact resistivity (ρc = 8.35 × 10−6 Ω · cm2), low leakage current (<10−6 A/mm), high ION/IOFF ratio (>105), a breakdown voltage of 2.55 kV, and a Baliga's figure of merit of 260 MW/cm2. This study demonstrates the optimization of the structural design of UWBG AlGaN channel HEMTs and its effect on transport properties to obtain state-of-the-art device performance.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (11)
Swarnav Mukhopadhyay
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Khush Gohel
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Surjava Sanyal
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Mayand Dangi
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Rajnin I. Roya
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Ruixin Bai
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Jiahao Chen
Spin-X Institute, School of Chemistry and Chemical Engineering, School of Biomedical Sciences and Engineering, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, State Key Laboratory of Luminescent Materials and Devices
Qinchen Lin
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Guangying Wang
Chirag Gupta
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,
Shubhra S. Pasayat
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706,