Interface trapping in (201) β-Ga2O3 MOS capacitors with deposited dielectrics

Asanka Jayawardena, Rahul P. Ramamurthy, Ayayi C. Ahyi, Dallas Morisette, Sarit Dhar

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The electrical properties of interfaces and the impact of post-deposition annealing have been investigated in gate oxides formed by low pressure chemical vapor deposition (LPCVD SiO2) and atomic layer deposition (Al2O3) on (201) oriented n-type β-Ga2O3 single crystals. Capacitance-voltage based methods have been used to extract the interface state densities, including densities of slow 'border' traps at the dielectric-Ga2O3 interfaces. It was observed that SiO2-β-Ga2O3 has a higher interface and border trap density than the Al2O3-β-Ga2O3. An increase in shallow interface states was also observed at the Al2O3-β-Ga2O3 interface after post-deposition annealing at higher temperature suggesting the high temperature annealing to be detrimental for Al2O3-Ga2O3 interfaces. Among the different dielectrics studied, LPCVD SiO2 was found to have the lowest dielectric leakage and the highest breakdown field, consistent with a higher conduction band-offset. These results are important for the processing of high performance β-Ga2O3 MOS devices as these factors will critically impact channel transport, threshold voltage stability, and device reliability.

Original languageEnglish
Article number192108
Number of pages5
JournalApplied Physics Letters
Issue number19
Publication statusPublished - 7 May 2018
Externally publishedYes

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