Details

Autor(en) / Beteiligte

• Sharma, Shivam
• Meng, Lingyu
• Bhuiyan, A. F. M. Anhar Uddin
• Feng, Zixuan
• Eason, David
• Zhao, Hongping
• Singisetti, Uttam

Titel

Vacuum Annealed β-Ga2O3 Recess Channel MOSFETs With 8.56 kV Breakdown Voltage

Ist Teil von

• IEEE electron device letters, 2022-12, Vol.43 (12), p.2029-2032

Ort / Verlag

New York: IEEE

Erscheinungsjahr

2022

Quelle

IEEE Electronic Library (IEL)

Beschreibungen/Notizen

• This letter reports vacuum annealing of lateral field-plated <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga2O3 MOSFETs with significant current recovery and improvement in the on-state resistance, <inline-formula> <tex-math notation="LaTeX">\text{R}_{\text {on}} </tex-math></inline-formula>, after Reactive Ion Etching (RIE) induced damage. We fabricate and characterize MOSFETs based on Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapor Deposition (MOCVD) grown <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga2O3 wafers to better understand the effects of vacuum annealing. We see a clear trend of vacuum annealed devices showing no reduction in breakdown voltages, <inline-formula> <tex-math notation="LaTeX">\text{V}_{\text {br}} </tex-math></inline-formula>, as compared to polymer passivated MOSFETs. This trend holds for identical gate-drain separation, <inline-formula> <tex-math notation="LaTeX">\text{L}_{\text {gd}} </tex-math></inline-formula>, varying from <inline-formula> <tex-math notation="LaTeX">20 ~\mu \text{m} </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">60 ~\mu \text{m} </tex-math></inline-formula>. Devices show up to 10 times reduction in <inline-formula> <tex-math notation="LaTeX">\text{R}_{\text {on}} </tex-math></inline-formula> as compared to previously reported <inline-formula> <tex-math notation="LaTeX">\text{R}_{\text {on}} </tex-math></inline-formula> for SU-8 passivated devices. For MBE sample, <inline-formula> <tex-math notation="LaTeX">\text{V}_{\text {br}} </tex-math></inline-formula> of 7.16 kV for a <inline-formula> <tex-math notation="LaTeX">\text{L}_{\text {gd}} </tex-math></inline-formula> = <inline-formula> <tex-math notation="LaTeX">40 ~\mu \text{m} </tex-math></inline-formula> device, with an average field strength of 1.79 MVcm<inline-formula> <tex-math notation="LaTeX">^{{-{1}}} </tex-math></inline-formula> and peak drain current density of 40 mA/mm, is reported. <inline-formula> <tex-math notation="LaTeX">\text{R}_{\text {on}} </tex-math></inline-formula> is <inline-formula> <tex-math notation="LaTeX">897 \Omega </tex-math></inline-formula>. mm, giving Baliga's Figure of Merit (BFOM) as 5.71 MWcm<inline-formula> <tex-math notation="LaTeX">^{{-{2}}} </tex-math></inline-formula>. For a <inline-formula> <tex-math notation="LaTeX">\text{L}_{\text {gd}} </tex-math></inline-formula> = <inline-formula> <tex-math notation="LaTeX">60 ~\mu \text{m} </tex-math></inline-formula> device, we report record high breakdown of 8.56 kV with BFoM of 4.9 MWcm<inline-formula> <tex-math notation="LaTeX">^{{-{2}}} </tex-math></inline-formula>. For MOCVD grown sample, a <inline-formula> <tex-math notation="LaTeX">\text{L}_{\text {gd}} </tex-math></inline-formula> = <inline-formula> <tex-math notation="LaTeX">60 ~\mu \text{m} </tex-math></inline-formula> device has <inline-formula> <tex-math notation="LaTeX">\text{V}_{\text {br}} </tex-math></inline-formula> of 6.11 kV, <inline-formula> <tex-math notation="LaTeX">\text{R}_{\text {on}} </tex-math></inline-formula> of 1.98 <inline-formula> <tex-math notation="LaTeX">\text{k}\Omega </tex-math></inline-formula>. mm and corresponding BFoM of 1.88 MWcm<inline-formula> <tex-math notation="LaTeX">^{{-{2}}} </tex-math></inline-formula>. Transfer Length Method (TLM) analysis indicates incomplete post etch current recovery after vacuum annealing.