An Efficient Design Approach to Optimize the Drift Layer of Unipolar Power Devices in 4H-SiC

Abstract

This paper reports generalized design solutions for the punch-through and nonpunch-through drift layers in 4H-SiC. In general, the critical electric field relation of Konstantinov is widely used to design the drift parameters in 4H-SiC due to its accuracy. In this paper, a fitted version of Konstantinov's critical electric field relation is used to derive the generalized optimum parameters for the drift design. The derived set of equations not only offers straightforward design of optimum drift parameters avoiding complex mathematical evaluations but also provide a meaningful insight to the drift design in 4H-SiC. From derived expressions, an inter-relation between the optimum punch-through and nonpunch-through structures is attained. For the punch-through structure, it was observed that optimum doping concentration and width for Konstantinov critical electric field model are 8% and 21.4% lower than that of the nonpunch-through structure. Consequently, the specific on-resistance for the punch-through structure is 14.9% lower than that of the nonpunch-through structure.

Keywords

• Punch-through
• nonpunch-through
• drift layer
• epitaxial layer
• breakdown voltage
• critical electric field