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 Ω/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 cm2, the value of P sp would be lower than 10%.

Определение параметров латерального и нестационарного шнурового токов в цилиндрическом халькогенидном стеклообразном полупроводнике

The heat-conduction equation describing the current cord in a semiconductor is approximately solved for a Ge–Sb–Te semiconductor system of cylindrical configuration. It is shown that the cord current at infinitely long times is proportional to the squared maximum temperature at the cord center and inversely proportional to the applied electric field. The scale of the lateral current perpendicular to the main cord current is estimated. It is found that the lateral current is low in comparison with the cord current; hence, the formation of lateral cords growing from the main cord is highly improbable.