Analytical Modeling and Design of Gallium Oxide Schottky Barrier Diodes Beyond Unipolar Figure of Merit Using High-k Dielectric Superjunction Structures

This work presents the design of beta-Ga2O3 schottky barrier diode using high-k dielectric superjunction to significantly enhance the breakdown voltage vs on-resistance trade-off beyond its already high unipolar figure of merit. The device parameters are optimized using both TCAD simulations and analytical modeling using conformal mapping technique. The dielectric superjunction structure is found to be highly sensitive to the device dimensions and the dielectric constant of the insulator. The aspect ratio, which is the ratio of the length to the width of the drift region, is found to be the most important parameter in designing the structure and the proposed approach only works for aspect ratio much greater than one. The width of the dielectric layer and the dielectric constant also plays a crucial role in improving the device properties and are optimized to achieve maximum figure of merit. Using the optimized structure with an aspect ratio of 10 and a dielectric constant of 300, the structure is predicted to surpass the b-Ga2O3 unipolar figure of merit by four times indicating the promise of such structures for exceptional FOM vertical power electronics.