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 onstate in current spreading region for a specific chip. The linear specific spreading resistance at the on-state is calculated to be8.6 Ω/cm in the fabricated chips. The proportion of the lateral spreading current in total forward current(Psp) is related to anode voltage and the chip area. Psp is increased with the increase in the anode voltage during initial on-state and then tends to a stable value. The stable values of Psp 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(Ksp) is also calculated and compared with Psp. The Ksp values of the two fabricated chips are calculated to be 31.94% and 57.75%. The values of Ksp and Psp are close with each other in a specific chip. The calculated Ksp can be used to predict that when the chip area of SiC SBD becomes larger than 0.5 cm2, the value of Psp would be lower than 10%.