A new, high-voltage 4H-SiC lateral dual sidewall Schottky (LDSS) rectifier: theoretical investigation and analysis

In this paper, we report a new 4 H-silicon carbide (SiC) lateral dual sidewall Schottky (LDSS) rectifier on a highly doped drift layer consisting of a high-barrier sidewall Schottky contact on top of the low-barrier Schottky contact. Using two-dimensional (2-D) device simulation, the performance of the proposed device has been evaluated in detail by comparing its characteristics with those of the compatible lateral conventional Schottky (LCS) and lateral trench sidewall Schottky (LTSS) rectifiers on 4H-SiC. From our simulation results, it is observed that the proposed LDSS rectifier acts as a low-barrier LTSS rectifier under forward-bias conditions, and as a high-barrier LTSS rectifier under reverse-bias conditions, making it an ideal rectifier. The LDSS rectifier exhibits an on/off current ratio (at 1 V/-500 V) of 5.5×10⁷ for an epitaxial layer doping of 1×10¹⁷ /cm³. Further, the proposed LDSS structure exhibits a very sharp breakdown similar to that of a p-i-n diode in spite of using only Schottky junctions in the structure. We have analyzed the reasons for the improved performance of the LDSS.