High temperature high voltage packaging of wideband gap semiconductors using gas insulating medium

Using wideband gap semiconductors (SiC, GaN) appear as possible solution to the growing demand for the development of high temperature power electronics. These devices are devoted to work in harsh environments mainly for "on board applications" like automobile, aircraft and space exploration. In some cases, high temperature is associated to the environment itself (when the converter is located in the vicinity of a thermal engine for example) but in other, it is only related to the increase of the power density associated to power integration. However, the opportunities given by these wideband gap semiconductors devices may be reduced since their packages are inadequate as regards insulation, interconnection and thermal management under high-temperature operations and environments. The aim of this paper is to present the results obtained concerning the insulating parts of this packaging, mainly secondary passivation and encapsulation in a 200-450°C temperature range. Gas insulation is used and this original solution is examined for different gases and conditions.