1 kV Self-Aligned Vertical GaN Superjunction Diode

Abstract

This work demonstrates vertical GaN superjunction (SJ) diodes fabricated via a novel self-aligned process. The SJ comprises n-GaN pillars wrapped by the charge-balanced p-type nickel oxide (NiO). After the NiO sputtering around GaN pillars, the self-aligned process exposes the top pillar surfaces without the need for additional lithography or a patterned NiO etching which is usually difficult. The GaN SJ diode shows a breakdown voltage (B V) of 1100 V, a specific on-resistance ( RON) of 0.4 mΩ⋅ cm2, and a SJ drift-region resistance ( Rdr) of 0.13 mΩ⋅ cm2. The device also exhibits good thermal stability with B V retained over 1 kV and RON dropped to 0.3 mΩ⋅ cm2 at 125oC . The trade-off between B V and Rdr is superior to the 1D GaN limit. These results show the promise of vertical GaN SJ power devices. The self-aligned process is applicable for fabricating the heterogeneous SJ based on various wide- and ultra-wide bandgap semiconductors.

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Citation
Y. Ma, M. Porter, Y. Qin, J. Spencer, Z. Du, M. Xiao, Y. Wang, I. Kravchenko, D. P. Briggs, D. K. Hensley, F. Udrea, M. Tadjer, H. Wang, and Y. Zhang, “1 kV Self-Aligned Vertical GaN Superjunction Diode,” IEEE Electron Device Lett., vol. 45, no. 1, pp. 12–15, Jan. 2024, doi: 10.1109/LED.2023.3332855.