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1. Schottky diode characteristics on high-growth rate LPCVD β -Ga 2 O 3 films on (010) and (001) Ga 2 O 3 substrates

   https://doi.org/10.1063/5.0083659  

   Saha, Sudipto; Meng, Lingyu; Feng, Zixuan; Anhar Uddin Bhuiyan, A. F.; Zhao, Hongping; Singisetti, Uttam (March 2022, Applied Physics Letters)

   High crystalline quality thick β-Ga 2 O 3 drift layers are essential for multi-kV vertical power devices. Low-pressure chemical vapor deposition (LPCVD) is suitable for achieving high growth rates. This paper presents a systematic study of the Schottky barrier diodes fabricated on four different Si-doped homoepitaxial β-Ga 2 O 3 thin films grown on Sn-doped (010) and (001) β-Ga 2 O 3 substrates by LPCVD with a fast growth rate varying from 13 to 21  μm/h. A higher temperature growth results in the highest reported growth rate to date. Room temperature current density–voltage data for different Schottky diodes are presented, and diode characteristics, such as ideality factor, barrier height, specific on-resistance, and breakdown voltage are studied. Temperature dependence (25–250 °C) of the ideality factor, barrier height, and specific on-resistance is also analyzed from the J–V–T characteristics of the fabricated Schottky diodes. 

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2. Quasi-vertical β-Ga2O3 Schottky diodes on sapphire using all-LPCVD growth and plasma-free Ga-assisted etching

   https://doi.org/10.1063/5.0280191  

   Khan, Saleh Ahmed; Ibreljic, Ahmed; Bhuiyan, A_F_M_Anhar Uddin (September 2025, APL Electronic Devices)

   This work demonstrates quasi-vertical β-Ga2O3 Schottky barrier diodes (SBDs) fabricated on c-plane sapphire substrates using an all-low-pressure chemical vapor deposition (LPCVD)-based, plasma-free process flow that integrates both epitaxial growth of a high-quality β-Ga2O3 heteroepitaxial film with in situ Ga-assisted β-Ga2O3 etching. A 6.3 μm thick (2̄01) oriented β-Ga2O3 epitaxial layer structure was grown on c-plane sapphire with 6° miscut, comprising a moderately Si-doped (2.1 × 1017 cm−3) 3.15 μm thick drift layer and a heavily doped (1 × 1019 cm−3) contact layer on an unintentionally doped buffer layer. Mesa isolation was achieved via Ga-assisted plasma-free LPCVD etching, producing ∼60° inclined mesa sidewalls with an etch depth of 3.6 μm. The fabricated SBDs exhibited excellent forward current–voltage characteristics, including a turn-on voltage of 1.22 V, an ideality factor of 1.29, and a Schottky barrier height of 0.83 eV. The minimum differential specific on-resistance was measured to be 8.6 mΩ cm2, and the devices demonstrated high current density capability (252 A/cm2 at 5 V). Capacitance–voltage analysis revealed a net carrier concentration of 2.1 × 1017 cm−3, uniformly distributed across the β-Ga2O3 drift layer. Temperature-dependent J–V–T measurements, conducted from 25 to 250 °C, revealed thermionic emission-dominated transport with strong thermal stability. The Schottky barrier height increased from 0.80 to 1.16 eV, and the ideality factor rose modestly from 1.31 to 1.42 over this temperature range. Reverse leakage current remained low, increasing from ∼5 × 10−6 A/cm2 at 25 °C to ∼1 × 10−4 A/cm2 at 250 °C, with the Ion/Ioff ratio decreasing from ∼1 × 107 to 5 × 105. The devices achieved breakdown voltages ranging from 73 to 100 V, corresponding to parallel-plate electric field strengths of 1.66–1.94 MV/cm. These results highlight the potential of LPCVD-grown and etched β-Ga2O3 devices for high-performance, thermally resilient power electronics applications. 

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3. Characterization of (001) β -Ga2O3 Schottky diodes with drift layer grown by MOCVD

   https://doi.org/10.1063/5.0155622  

   P. Sundaram, Prakash; Liu, Fengdeng; Alema, Fikadu; Osinsky, Andrei; Jalan, Bharat; Koester, Steven J. (June 2023, Applied Physics Letters)

   Growing a thick high-quality epitaxial layer on the β-Ga2O3 substrate is crucial in commercializing β-Ga2O3 devices. Metal organic chemical vapor deposition (MOCVD) is also well-established for the large-scale commercial growth of β-Ga2O3 and related heterostructures. This paper presents a systematic study of the Schottky barrier diodes fabricated on two different Si-doped homoepitaxial β-Ga2O3 thin films grown on Sn-doped (001) and (010) β-Ga2O3 substrates by MOCVD. X-ray diffraction analysis of the MOCVD-grown sample, room temperature current density–voltage data for different Schottky diodes, and C–V measurements are presented. Diode characteristics, such as ideality factor, barrier height, specific on-resistance, and breakdown voltage, are studied. Temperature dependence (170–360 K) of the ideality factor, barrier height, and Poole–Frenkel reverse leakage mechanism are also analyzed from the J–V–T characteristics of the fabricated Schottky diodes. 

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4. Record >10 MV/cm mesa breakdown fields in Al _0.85 Ga _0.15 N/Al _0.6 Ga _0.4 N high electron mobility transistors on native AlN substrates

   https://doi.org/10.1063/5.0083966  

   Khachariya, Dolar; Mita, Seiji; Reddy, Pramod; Dangi, Saroj; Dycus, J. Houston; Bagheri, Pegah; Breckenridge, M. Hayden; Sengupta, Rohan; Rathkanthiwar, Shashwat; Kirste, Ronny; et al (April 2022, Applied Physics Letters)

   The ultra-wide bandgap of Al-rich AlGaN is expected to support a significantly larger breakdown field compared to GaN, but the reported performance thus far has been limited by the use of foreign substrates. In this Letter, the material and electrical properties of Al 0.85 Ga 0.15 N/Al 0.6 Ga 0.4 N high electron mobility transistors (HEMT) grown on a 2-in. single crystal AlN substrate are investigated, and it is demonstrated that native AlN substrates unlock the potential for Al-rich AlGaN to sustain large fields in such devices. We further study how Ohmic contacts made directly to a Si-doped channel layer reduce the knee voltage and increase the output current density. High-quality AlGaN growth is confirmed via scanning transmission electron microscopy, which also reveals the absence of metal penetration at the Ohmic contact interface and is in contrast to established GaN HEMT technology. Two-terminal mesa breakdown characteristics with 1.3  μm separation possess a record-high breakdown field strength of ∼11.5 MV/cm for an undoped Al 0.6 Ga 0.4 N-channel layer. The breakdown voltages for three-terminal devices measured with gate-drain distances of 4 and 9  μm are 850 and 1500 V, respectively. 

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5. Extreme bandgap polarization doped AlGaN layers on bulk AlN for pn-diodes with an 8.5 MV cm ⁻¹ breakdown field and forward current density exceeding 20 kA cm ⁻²

   https://doi.org/10.35848/1347-4065/add2b6  

   Jamil, Tariq; Mazumder, Abdullah_Al Mamun; Ali, Muhammad; Rahman, Mafruda; Stephenson, Kenneth; Simin, Grigory; Khan, Asif (May 2025, Japanese Journal of Applied Physics)

   Abstract In this paper we present a study of distribution polarization doped Al_xGa_1−xN layers and their use in quasi-vertical configuration pn-diodes which exhibited a high breakdown field of ∼8.5 MV cm⁻¹and a large forward current density (∼23 kA cm⁻²). We also establish their potential use in UVC light emitters by studying the optical emission from a quantum well inserted at the distribution polarization doped pn-junction interface. 

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