Passivation in High-Power Si Devices - An Overview

Abstract

Passivation of semiconductor devices reaches back to the 1950s with passivation of silicon surfaces by thermally grown oxides. Over the years, the concept has changed towards a detailed balance of breakdown field and leakage current capabilities, involving also the underlying termination areas. In this contribution, a brief historical overview of passivation of Si devices will be given. Based on the underlying physics and lessons learned, an outlook to the challenges for power devices from wide band gap materials, such as silicon carbide, is provided.

High-Voltage Temperature Humidity Bias Test (HV-THB): Overview of Current Test Methodologies and Reliability Performances

“…As seen in the previous sections, HV-THB applies a strong stress to the DUTs, and as highlighted by several studies [2,6,10,21,35,[46][47][48][49][50] the optimization of power semiconductor devices against humidity-voltage phenomena is strictly related to the intertwined roles of both the passivation stack and the structure of the junction termination, where field peaks are generally localized and can trigger humidity related degradation processes [6,[49][50][51].…”

“…As shown in Figure 10, monitoring can be challenging since leakage values are extremely low and many devices must be monitored at the same time [2,18]. Passivation stacks for SiC devices show promising results with the use of AlN and HfO2 due to their high dielectric constants and higher critical electric fields [49,65]. The device simulations reported in Figure 11 show a comparison of three different passivation materials applied to a SiC device.…”

“…In this simulation work, a good reduction of the electric field peak was achieved with an HfO2 layer applied to the termination region. In this way enhanced shrinking of SiC power devices becomes viable not only for their thermal performances, which are ensured by the physical properties Passivation stacks for SiC devices show promising results with the use of AlN and HfO 2 due to their high dielectric constants and higher critical electric fields [49,65]. The device simulations reported in Figure 11 show a comparison of three different passivation materials applied to a SiC device.…”