Analysis of premature breakdown in high-power devices using IBIC microscopy

Abstract

Ion beam induced charge (IBIC) microscopy is used mainly for analysis of various semiconductor parameters such as diffusion length and lifetime of the charge carriers. In this paper, we show that IBIC microscopy is also useful for the visualization of the electrical field distribution within depletion regions of electronic devices. The ions penetrating into the semiconductor generate electron-hole pairs that are separated and accelerated depending on the internal electric field distribution. The shape of the resulting current induced in this way is dependent on the electric field. This dependence and the large penetration depth of the light ions allow the analysis of electric field distributions within semiconductor devices up to a few tens of microns below the device surface. Therefore, IBIC microscopy is a very useful analytical tool for the characterization of the electrical field distribution within high-power devices, even when the semiconductor is covered with thick passivation or metallization layers