Interface Charge Characteristics of Silicone Elastomer/AlN Double Layer Dielectric Used in the Power Module Under DC Voltage

Silicone elastomer and AlN (Aluminium nitride) is commonly used as insulation structure in high-voltage silicon carbide power electronic devices. Under the strong electric field, there is space charge accumulation at the interface, which affect the electric field distribution and further affect its insulation performance. In this paper, the interface charge characteristics of silicone elastomer and AlN are studied by using Pulsed Electro-Acoustic (PEA) method. The experimental results show that there is space charge accumulation at the interface of silicone elastomer and AlN. A method for calculating the electric field at the interface between metal and dielectric in double-layer dielectric structure is presented. In addition, a calculation method of dielectric interface charge density considering the influence of space charge is proposed.