Akhila Mattapalli | Searcharxiv

arXiv2026

4 MV/cm (010) $β$-Ga$_2$O$_3$ Heterojunction Diodes Realized by Low-Damage e-Beam NiO$_x$ Interlayers

We report on the utilization of a low-damage e-beam NiO$_x$ deposition process to realize field-plated heterojunction diodes (FP-HJDs) on (010) $β$-Ga$_2$O$_3$ films with high critical breakdown field strengths beyond 4 MV/cm and power figure of merits (PFOM) of >1 GW/cm$^2$. Diodes were fabricated on a 2.67 $\times$ 10$^{16}$ cm$^{-3}$ intentionally doped 6.2 $μ$m thick epitaxial layer grown by metalorganic chemical vapor deposition (MOCVD) on a conductive Sn-doped $β$-Ga$_2$O$_3$ (010) substrate using TMGa, O$_2$, Ar carrier gas, and SiH$_4$ as the silicon dopant source. The mesa etched FP-HJD devices utilized a thin 7 nm e-beam NiO$_x$ interlayer before the sputtered NiO$_x$ layers to eliminate the effects of sputter-induced ion damage on the (010) epilayers. Current-Voltage measurements resulted in a forward current density of 700 A/cm$^2$ at 4 V, HJD ideality factor of 1.29, a V$_{bi}$ of 2 V, rectification ratio of 10$^{11}$, and a differential specific on resistance (R$_{on,sp}$) value of 2.36 m$Ω$ $\times$ cm$^2$. Breakdown of the (010) FP-HJDs was 1.64 kV, leading to a parallel plane electric field at breakdown (E$_{||,max}$) of 4.02 MV/cm and a PFOM of 1.14 GW/cm$^2$, which is a state-of-the-art result for diodes on MOCVD-grown (010) drift layers.

cond-mat.mtrl-sci↗

arXiv2025

Kilovolt-Class $β-Ga_2O_3$ Field-Plated Schottky Barrier Diodes with MOCVD-Grown Intentionally $10^{15}$ $cm^{-3}$ Doped Drift Layers

We report on the growth optimization of intentionally low-doped ($10^{15}$ $cm^{-3}$) high-quality $β-Ga_2O_3$ drift layers up to 10 $μm$ thick via MOCVD and the fabrication of kilovolt-class field plated Schottky barrier diodes on these thick drift layers. Homoepitaxial growth was performed on (010) $10^{15}$ $cm^{-3}$ substrates using TMGa as the Ga precursor. Growth parameters were systematically optimized to determine the best conditions for high quality thick growths with the given reactor geometry. Chamber pressure was found to improve the growth rate, mobility, and roughness of the samples. Growth rates of up to 7.2 $μm$/hr., thicknesses of up to 10 $μm$, Hall mobilities of up to 176 $cm^2$/Vs, RMS roughness down to 5.45 nm, UID concentrations as low as $2 \times$ $10^{15}$ $cm^{-3}$, and controllable intentional doping down to $3 \times$ $10^{15}$ $cm^{-3}$ were achieved. Field plated Schottky barrier diodes (FP-SBDs) were fabricated on a $6.5 \times$ $10^{15}$ $cm^{-3}$ intentionally doped 10 $μm$ thick film to determine the electrical performance of the MOCVD-grown material. The FP-SBD was found to have current density $>$100 A/$cm^2$ at 3 V forward bias with a specific differential on resistance ($R_{on,sp}$) of 16.22 m$Ω$.$cm^2$ and a turn on voltage of 1 V. The diodes were found to have high quality anode metal/semiconductor interfaces with an ideality factor of 1.04, close to unity. Diodes had a maximum breakdown voltage of 1.50 kV, leading to a punch-through maximum field of 2.04 MV/cm under the anode metal, which is a state-of-the-art result for SBDs on MOCVD-grown (010) drift layers.

physics.app-ph↗