Space Charge Characteristic of Silicone Elastomer Used in SiC Device Under High Temperature up to 200 °C

Abstract

In order to study the space charge characteristics of silicone elastomers at high temperatures, a high-temperature pulse electro-acoustic (PEA) space charge characteristic measurement system with a temperature range of room temperature ( $25~^{\circ }$ C)– $200~^{\circ }$ C was developed in this article. The system developed in this article can meet the temperature control and measurement requirements through actual temperature measurement and calibration. Through this system, this article studies the space charge characteristics and short-circuit characteristics of silicone elastomers under different polarity dc voltages in the range of $25~^{\circ }$ C– $200~^{\circ }$ C. With the increase of temperature, the charge accumulation depth first increases and then decreases, and the charge accumulation amount first increases and then decreases. The migration rate of negative polarity charges is greater than that of positive polarity charges. The trap characteristics of silicone elastomers at different temperatures are analyzed by charge dissipation characteristics. At lower temperatures, the deep trap density is greater than the shallow trap density, whether it is electron traps or hole traps. When it is greater than a certain temperature, the shallow trap density is greater than the deep trap density. Temperature affects charge generation and charge migration. At low temperatures, the charge injection amount increases and becomes the dominant factor. When the temperature increases, the charge mobility increases and becomes the dominant factor, so the charge accumulation amount and trap density both increase and then decrease with temperature.