Nb${}_2$O${}_5$ high-k dielectric enabled electric field engineering of $\beta$-Ga${}_2$O${}_3$ metal-insulator-semiconductor (MIS) diode

Abstract

We demonstrate an Nb${}_2$O${}_5$/$\beta$-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 $\beta$-Ga${}_2$O${}_3$ Schottky barrier diode. The 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$\times$ lower electric field at the metal/dielectric interface in the MIS diode compared to the metal/$\beta$-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${}_5$ w.r.t $\beta$-Ga${}_2$O${}_3$, the MIS design led to a 3$\times$ improvement in the reverse blocking voltage with a slight trade-off in the specific on-resistance. Overall, a 3.3$\times$ 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 2-D TCAD simulations.

arXiv commentThe following article has been submitted to 'Journal of Applied Physics' and the link will be updated if it gets published

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Cited by in corpus (1)

• Electric field management in $\beta$-$G{a}_2{O}_3$ vertical Schottky diodes using high-k bismuth zinc niobium oxide