Electrical behavior of commercial off-the-shelf normally-off GaN power transistors under heavy ion irradiation is presented based on technology computer aided design numerical simulation in order to better understand the mechanism of single event effects (SEEs) in these devices. First, the worst case has been defined from the single event transient mechanism. Then, the decrease in the electric field observed after irradiation and the traps effect have been addressed. Finally, possible mechanisms of SEE in these devices under heavy ion are proposed.

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International audienceDiamond is a promising material for future high voltage applications because of its high critical electric field. This property leads to new constraints on the used termination structure, especially in terms of electric field value. For this reason, new termination architectures based on field plate are proposed for diamond Schottky diodes. Using finite element simulations with Sentaurus TCAD (technology computer-aided design) software, a new field plate structure has been proposed. Simple variations in the classic field plate architecture were sufficient to increase the breakdown voltage from 1632 V to 2141 V at 700 K, but not to reduce the electric field value at the edges of field plate. Several termination topologies have been proposed to solve this problem. Parametric simulations were used to optimize the geometrical termination structure in order to reduce the electric field peak value at its edge while maintaining high breakdown voltage. The new solutions have helped reducing the maximum electric field from 57 MV/cm down to 22.7 MV/cm

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Smart power technologies are required to withstand high-electrostatic-discharge (ESD) robustness under both powered and unpowered conditions, particularly for automotive and aeronautic applications among many others. They are concurrently confronted to the challenges of high-temperature operation in order to reduce heat-sink-related costs. In this context, very compact high-robustness ESD protections with low sensitivity to temperature are required. To fulfill this need, we studied a new ESD protection structure that combines in the same component MOS, IGBT, and thyristor effects. This is achieved by inserting in the same LDMOS device P + diffusions in the drain. We studied the impact of N + /P + ratios on R ON and holding current at high temperatures. Structure optimization has been realized with 3-D TCAD simulation and experimentally validated. The proposed structures provide high ESD robustness with small footprint and reduced temperature sensitivity compared with classical solutions. Original design solutions to improve their immunity to latchup are also presented.

We present backside laser testing of GaN power devices on Si substrate using optical parameters compatible with three-photon absorption in GaN and single-photon absorption in the substrate. The laser/device interaction is described. Two different kinds of transients are observed at the gate electrode and analyzed. The technique allows identifying the sensitive regions of the devices and generating destructive events.

Using finite element simulations with Sentaurus TCAD (Technology Computer-Aided Design) software, a progress from simple and classic termination for a Schottky diode to new topology termination has been studied in this paper. A polyimide trench under field plate termination has been used. The efficiency increases from 67% for a simple field plate with optimum parameters up to 97%. The maximum electric field in the termination dielectric has been evaluated also. A wide study of the termination geometry has been made in order to extract the optimum parameters in two directions. The first one is to obtain a high efficiency regarding the breakdown voltage, and the second one is to have the minimum electric field peak at the termination edge.