Temperature Effects on Power MOSFET and IGBT Sensitivities toward Single Events S. Morand, F. Miller, P. Austin, P. Poirot, R. Gaillard, T. Carri` ere, and N. Buard Abstract—Proton accelerator and pulsed laser tests show that temperature induces large variations compared to room temperature for power electronic radiation sensitivity assessment. Index Terms—IGBT, Temperature, Burnout, Latch-Up, Pulsed Laser Stimulation, Proton radiation. I. I NTRODUCTION P OWER electronic devices represent an alternative to conventional power sources especially within automotive, space and aeronautic industries in which electronic systems have to sustain harsh conditions: extreme temperatures, mois- ture, structural dynamics, and electrical stresses coupled to the radiation environment constraint. This study paves the way to a methodology to evaluate working condition effects on radiation sensitivity and firstly temperature effects. IGBT (Insulated Gate Bipolar Transistor) and power MOS- FET (Metal Oxide Semiconductor Field Effect Transistor) exhibit a parasitic structure that may lead to permanent failures because of destructive mechanisms triggered by ionizing par- ticles [1-3] during forward blocking state. Power MOSFETs are vulnerable to Single Event Burnout (SEB), and IGBTs are susceptible to Single Event Latch-Up (SEL) or SEB. Radiation sensitivity is consequently a scaling factor for inverter appli- cations [4-6] as derating rules are followed to keep devices out of operating conditions likely to destructive single events. Power device operating mode leads to device self-heating from on-state and switching phases. Consequently, we propose to study the temperature effects on the triggering of device inner parasitic structures. Previous work [7] already showed effects from a temperature rise on two MOSFET references (IR6766 and IR150 power MOSFETs). For a given biasing voltage, single event burnout (SEB) worst case is reached at lower temperature. Low temperature enhances the current amplification in power MOSFET which is driven by the impact ionization mechanism as in the case of power diodes [2]. IGBTs have recently made a breakthrough in mid power HVDC (High Voltage Direct Current) applications and espe- cially on markets such as More Electrical Transports (A/C, Manuscript sent to RADECS 2011 on September, 16, 2011. S. Morand, F. Miller and N. Buard are with EADS France IW. 12 Rue Pasteur 92152 Suresnes Cedex France. Contact : sebastien.morand@eads.net, tel. +33 (0)1 46 97 35 26. P. Austin is with LAAS-CNRS, Toulouse, France. P. Poirot is with INFODUC, Igny, France. R. Gaillard is Consultant, Saint-Arnoult en Yvelines, France. T. Carriere is with EADS ASTRIUM Space Transportation, Les Mureaux, France. Automotive). We have taken a closer look at temperature effects on those devices since basic mechanisms involved are slightly different from power MOS and, as a result, room temperature characterization could lead to an underestimation of their sensitivity. In a first part, TCAD results are presented to show the expected temperature effect on the radiation sensitivity of NPT (Non Punch Through) IGBTs. Then, a specific test board is presented to couple thermal effects to radiation constrains. This setup is finally used under a proton beam and laser testing to demonstrate that the temperature effect on SEE in power electronics is related to the cell technology. II. TCAD DEVICE SIMULATIONS Sensitivities of power MOSFETs and IGBTs were inves- tigated considering temperature aspects. Simulations were performed on an academic 600V MOSFET cell layout (The breakdown voltage, V br is 650V ) and a non punch-through 500V IGBT cell (V br = 550V ). Due to symmetry, half cells were simulated and precise meshing was designed around the ionizing track and doping profile gradients [8-10]. Those 2D simulations are only qualitative approaches where analytical doping profiles are used and the ion track is fitted to a 2D structure. TABLE I TCAD BEAM PARAMETERS AND SIMULATION MODELS. Ion track parameters Beam waist 50nm Range 60μm Linear Energy Transfer (2D) 0.2pCμm −1∗ FWHM Beam pulse 2ps Physics TCAD Models for SEP Simulation Mobility models Electrical field, doping carrier-carrier scattering effects Generation & Auger generation and recombination recombination models SRH, Impact Ionization models Electronic Band Band Gap narrowing effects, Intrinsic structure density, Fermi stats Models are also a major concern since their dependencies over temperature give the trends for sensitivity evolution. The selected ones are given in Table I. The tested cell (Fig. 1) is set up to chosen bias conditions (V ds , V ce ) with the gate shorted to the ground (V gs =0 or V ge =0). Then the heavy 18 109