AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) using plasma deposited BN as gate dielectric

Contributors:   Tsung-Han Yang, Jesse Brown, Kai Fu, Jingan Zhou, Kevin Hatch, Chen Yang, Jossue Montes, Xin Qi, Houqiang Fu, Robert J. Nemanich, and Yuji Zhao
ABSTRACT
AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) were fabricated on Si substrates with a 10 nm boron nitride (BN) layer as a gate dielectric deposited by electron cyclotron resonance microwave plasma chemical vapor deposition. The material characterization of the BN/GaN interface was investigated by X-ray photoelectric spectroscopy (XPS) and UV photoelectron spectroscopy. The BN bandgap from the B1s XPS energy loss is ∼5 eV consistent with sp2 bonding. The MISHEMTs exhibit a low off-state current of 1 × 10−8 mA/mm, a high on/off current ratio of 109, a threshold voltage of −2.76 V, a maximum transconductance of 32 mS/mm at a gate voltage of −2.1 V and a drain voltage of 1 V, a subthreshold swing of 69.1 mV/dec, and an on-resistance of 12.75 Ω·mm. The interface state density (Dit) is estimated to be less than 8.49 × 1011 cm−2 eV−1. Gate leakage current mechanisms were investigated by temperature-dependent current–voltage measurements from 300 K to 500 K. The maximum breakdown electric field is no less than 8.4 MV/cm. Poole–Frenkel emission and Fowler–Nordheim tunneling are indicated as the dominant mechanisms of the gate leakage through the BN gate dielectric at low and high electric fields, respectively.

This work was supported in part by the ARPA-E PNDIODES Program monitored by Dr. Isik Kizilyalli under Grant No. DE-AR0000868 and in part by the NASA HOTTech Program under Grant No. 80NSSC17K0768. This work was also supported as part of ULTRA, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under Award No. DE-SC0021230. We acknowledge the use of facilities within the Eyring Materials Center at Arizona State University. The device fabrication was performed at the ASU NanoFab, which was supported by NSF Contract No. ECCS-1542160.

Publisher: Applied Physics Letters,   Volume: 118,   072102 ||  Published: ||   PDF (1.8 MB) ||   Read More...