Multi-kV Class β-Ga₂O₃ MESFETs With a Lateral Figure of Merit Up to 355 MW/cm

• Published in: IEEE electron device letters 2021-09, Vol.42 (9), p.1272-1275
• Main Authors: Bhattacharyya, Arkka, Ranga, Praneeth, Roy, Saurav, Peterson, Carl, Alema, Fikadu, Seryogin, George, Osinsky, Andrei, Krishnamoorthy, Sriram
• Format: Article
• Language: English
• Subjects: breakdown; Contact resistance; Depletion; Electric breakdown; Epitaxial growth; Epitaxial layers; Field effect transistors; field plates; Figure of merit; Gallium oxides; Ga₂O; kilovolt; lateral figure of merit; Logic gates; Low temperature; MESFETs; Metalorganic chemical vapor deposition; MOVPE; Passivation; regrown contacts; Silicon compounds; Silicon dioxide; Vapor phase epitaxy; Vapor phases
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3100802

We demonstrate over 3 kV gate-pad-connected field plated (GPFP) \beta -Ga 2 O 3 lateral MESFETs with high lateral figures of merit (LFOM) using metalorganic vapor phase epitaxy (MOVPE) grown channel layers and regrown ohmic contact layers. Using an improved low-temperature MOVPE selective area epitaxy process, we show that a total contact resistance to the channel as low as 1.4~\Omega .mm can be achieved. The GPFP design adopted here using plasma-enhanced chemical vapor deposited (PECVD) SiN x dielectric and SiN x /SiO 2 wrap-around passivation exhibits up to ~14% improved \text{R}_{{\text {ON}}} , up to ~70% improved breakdown voltage ( \text{V}_{{\text {BR}}}= \text {V}_{{\text {DS}}}-\text {V}_{{\text {GS}}} ) resulting in up to 3\times higher LFOM compared to the non-FP \beta -Ga 2 O 3 lateral MESFETs. The \text{V}_{{\text {BR}}} (~2.5 kV) and LFOM (355 MW/cm 2 ) measured simultaneously in our GPFP \beta -Ga 2 O 3 lateral MESFET (with \text{L}_{{\text {GD}}} = {10}\mu \text{m} ) is the highest value achieved in any depletion-mode \beta -Ga 2 O 3 lateral device to date.