Enhanced Charge Collection in Silicon Carbide Power MOSFETs Demonstarted by Pulsed-Laser Two-Photon Absroption SEE Experiments
Johnson, Robert Allen
A two-photon absorption technique is used to understand the mechanisms of single-event effects in silicon carbide power metal oxide field-effect transistors (MOSFETs) and power junction barrier Schottky diodes. The MOSFETs and diodes have similar structures enabling identification of effects associated specifically with the parasitic bipolar structure that is present in the MOSFETs, but not the diodes. The collected charge in the diodes varies only with laser depth, whereas it varies with depth and lateral position in the MOSFETs. Optical simulations demonstrate that the variations in collected charge observed are from the semiconductor device structure, and not from metal/passivation-induced reflection. The difference in the spatial dependence of collected charge between the MOSFET and diode is explained by bipolar amplification of the charge carriers in the MOSFETs. TCAD device simulations extend this analysis to heavy ion-induced charge collection.