β-Ga2O3 FinFETs with ultra-low hysteresis by plasma-free metal-assisted chemical etching

Abstract

In this work, β-Ga2O3 fin field-effect transistors (FinFETs) with metalorganic chemical vapor deposition grown epitaxial Si-doped channel layer on (010) semi-insulating β-Ga2O3 substrates are demonstrated. β-Ga2O3 fin channels with smooth sidewalls are produced by the plasma-free metal-assisted chemical etching (MacEtch) method. A specific on-resistance (Ron,sp) of 6.5 mΩ·cm2 and a 370 V breakdown voltage are achieved. In addition, these MacEtch-formed FinFETs demonstrate DC transfer characteristics with near zero (9.7 mV) hysteresis. The effect of channel orientation on threshold voltage, subthreshold swing, hysteresis, and breakdown voltages is also characterized. The FinFET with channel perpendicular to the [102] direction is found to exhibit the lowest subthreshold swing and hysteresis.

Catalytic nickel silicide as an alternative to noble metals in metal-assisted chemical etching of silicon

“…MACE fabricates various Si patterns such as wires, trenches, and holes from nano-to micro-scale regimes through a simpler process than other etching processes. [11][12][13][14][15] In MACE, Si is etched through two chemical reaction steps: oxidation and oxide removal. H 2 O 2 is a strong oxidant but does not directly oxidize Si in an HF/H 2 O 2 solution.…”

A Review of Recent Progress in β‐Ga2O3Epitaxial Growth: Effect of Substrate Orientation and Precursors in Metal–Organic Chemical Vapor Deposition

“…The 3D device structures can be obtained using the top–down etching of β‐Ga 2 O 3 films. [ 38–42 ] However, this discussion is out of scope of this review.…”

“…The 3D device structures can be obtained using the top-down etching of β-Ga 2 O 3 films. [38][39][40][41][42] However, this discussion is out of scope of this review. This review will focus on examining the prospects and status of Ga 2 O 3 epitaxial growth technologies and establishing an up-to-date database of optimal epitaxial growth conditions.…”

Anisotropic non-plasma HCl gas etching of a (010) β-Ga2O3 substrate

“…This is demonstrated by almost-zero-hysteresis transfer characteristics of MOS capacitors fabricated on the Ga-flux-etched surfaces 32) and MOS gates fabricated on MacEtch-formed fins. 33) In our previous study, we conducted selective-area etching on (001) β-Ga 2 O 3 substrates covered with patterned SiO 2 masks using HCl gas flow in a halide vapor phase epitaxy (HVPE) system without plasma excitation. 34) We observed that the etched structures were primarily dominated by crystal facets with low surface energy densities, and the striped windows along [010] created high-aspect-ratio fins and trenches with smooth (100)-faceted inclined sidewalls.…”

“…It should be noted that (010) orientation substrates are preferred for molecular beam epitaxy and metal-organic chemical vapor deposition compared to (001) ones. [35][36][37] Additionally, planar devices such as MESFETs, 1,20,38) MOSFETs, 5-7) MODFETs, 8) and FinFETs 33) have been fabricated on highquality epitaxial films on (010) substrates. Therefore, it is especially necessary to perform high-aspect-ratio etching on (010) substrates to form fins 33) and trenches (including recess structures) 5,7,20) to improve the field effect in the channels and/or breakdown voltages.…”