Can you provide a brief overview of the Diodes, Inc. Rectifier Die Glass Passivation Process (GPP)?
The Diodes Inc. Glass Passivation Process (GPP) for Rectifier Dice occurs in the wafer form after the Wafer Diffusion (P+) Process. Immediately after the Diffusion Process, the wafer is masked with a photoresist film and the dice are pattern etched through the junction plane, this operation is called mesa etching. The exposed p-n junction surface is then passivated in a two-layer process. • First, an oxygen doped, Semi-Insulating Poly Crystalline Silicon (SIPOS) layer is deposited onto the silicon junction surface by Low Pressure Chemical Vapor Deposition (LPCVD) to stabilize the region. • Second, a thick layer of fired – on, high temperature glass is deposited over the SIPOS layer and protects the junction from ambient contamination and mechanical damage. The wafers are then masked with a photoresist film and the top (Anode) Contact Metallization Layer of sintered nickel is applied (see figure 1). Figure 1.