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Nb<inf>2</inf>O<inf>5</inf>high-k dielectric enabled electric field engineering of β -Ga<inf>2</inf>O<inf>3</inf>metal-insulator-semiconductor (MIS) diode
Journal
Journal of Applied Physics
ISSN
00218979
Date Issued
2021-12-28
Author(s)
Tiwari, Prabhans
Biswas, Jayeeta
Joishi, Chandan
Lodha, Saurabh
Abstract
We demonstrate an Nb 2 O 5 / β - Ga 2 O 3 metal-insulator-semiconductor (MIS) hetero-junction diode with Nb 2 O 5 as the high-k dielectric insulator for more efficient electric field management resulting in enhanced breakdown characteristics compared to a β - Ga 2 O 3 Schottky barrier diode. Nb 2 O 5 dielectric films were grown using atomic layer deposition and exhibited a high dielectric constant of 50. The high dielectric constant resulted in a 5 × lower electric field at the metal/dielectric interface in the MIS diode compared to the metal/ β - Ga 2 O 3 interface in the Schottky barrier diode. With good electron conduction in forward bias enabled by the negative conduction band offset of Nb 2 O 5 with respect to β - Ga 2 O 3, the MIS design led to a 3 × improvement in the reverse blocking voltage with a slight trade-off in the specific on-resistance. Overall, a 3.3 × increase in the power figure of merit was observed (3.25 MW / cm 2 for the Schottky diode and 10.8 MW / cm 2 for the MIS diode). A detailed analysis of the energy band line-up and the forward and reverse current transport mechanisms are also presented using analytical modeling and 2D technology computer-aided design simulations.
Volume
130
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