Investigation of lateral spreading current in the 4H-SiC Schottky barrier diode chip

Lateral current spreading in the 4H-SiC Schottky barrier diode (SBD) chip is investigated. The 4H-SiC SBD chips with the same vertical parameters are simulated and fabricated. The results indicate that there is a fixed spreading resistance at on-state in current spreading region for a specific chip. The linear specific spreading resistance at the on-state is calculated to be 8.6 omega/cm in the fabricated chips. The proportion of the lateral spreading current in total forward current (P (sp)) is related to anode voltage and the chip area. P (sp) is increased with the increase in the anode voltage during initial on-state and then tends to a stable value. The stable values of P (sp) of the two fabricated chips are 32% and 54%. Combined with theoretical analysis, the proportion of the terminal region and scribing trench in a whole chip (K (sp)) is also calculated and compared with P (sp). The K (sp) values of the two fabricated chips are calculated to be 31.94% and 57.75%. The values of K (sp) and P (sp) are close with each other in a specific chip. The calculated K (sp) can be used to predict that when the chip area of SiC SBD becomes larger than 0.5 cm(2), the value of P (sp) would be lower than 10%.