JBS Device Design and Post-Etch Surface Repair Process Research

GaN quasi-vertical power devices are of high research value because of their ability to introduce current and electric field into the device body, as well as their ability to realize large-area process production at low cost. In this paper, a GaN-based Junction Barrier Schottky diode (JBS) is designed. Firstly, the relationship between the doping concentration of P
⁺
-GaN layer, the doping concentration of N
^-
-GaN layer, reverse voltage and depletion layer width of the JBS device is theoretically calculated, and then the etching of the secondary epitaxial window as well as the surface restoration process are investigated. The P
⁺
-GaN layer was etched using photoresist mask and SiO
2
mask, and the etched step was treated with TMAH solution and KOH solution. The SEM (Scanning Electron Microscope) test results show that the GaN stage etching with SiO
2
as a mask and the treatment of the stage with TMAH solution is flatter and smoother, which is more favorable for the subsequent secondary epitaxy process. Combining the above results, the epitaxial parameters of the JBS device are designed as follows: the concentration of the P
⁺
-GaN layer is 1×10
¹⁷
cm
^-3
, and the doping concentration of the N
^-
-GaN layer is 2×10
¹⁶
cm
^-3
; among the processes, SiO
2
is used as a mask for the GaN step etching, and TMAH solution is used to repair the etched surface.