Turn-on Of Parasitic Bipolar Transistor Research Articles

Application of a novel test system to characterize single-event effects at cryogenic temperatures

Details of a customized cryogenic test system for use in in situ single-event radiation tests on semiconductor devices at cryogenic temperatures are presented. The lightweight portable system is designed for performing heavy-ion broadbeam single-event radiation testing at different beam facilities. It is designed for use with either liquid nitrogen or liquid helium as cryogens, depending on the desired lower temperature limit. A controlled heating system on the inside allows for single-event radiation tests as a function of temperature. To enable single-event strikes at angles, the device under test can be rotated about a vertical axis without having to break vacuum. Electrical connectivity to the device under test is provided through six fully customizable hermetically sealed connecting ports. The system has been used to conduct single-event tests over temperature on a test circuit fabricated in IBM CMOS 130 nm technology. Single-event transient pulse widths were found to increase by up to 30% as the temperature was varied from −135 °C to +20 °C. Device simulations indicate that single-event-induced parasitic bipolar transistor turn-on in the n-well of PMOS transistors is responsible for the observed increase in pulse widths across the temperature ranges considered.

Single-Event Burnout and Avalanche Characteristics of Power DMOSFETs

Analyses of quasi-stationary avalanche simulations on radiation-hardened power MOSFETs suggest that the single-event burnout (SEB) failure is determined by the device's avalanche characteristics and confirm SEB failure mechanism is due to the turn-on of parasitic bipolar transistor. The heavy ion beam is only acting as a trigger. Simulation results on various 600 V and 250 V radiation-hardened power MOSFETs from International Rectifier are compared to an extensive set of single event effect test results and prove quasi-stationary avalanche simulation is capable of evaluating and predicting SEB susceptibility

Short-Channel Effect Suppression In Silicon Carbide Power Mesfets

ABSTRACTWe demonstrate that the performance of silicon carbide MESFETs is largely determined by short-channel effects. Parasitic bipolar transistor turn-on limits the operation voltage to a small fraction of the theoretically expected value for an ideal device. Tradeoffs are shown to exist between optimum gate length and on-state current on one hand, and the maximum blocking voltage on the other hand. Composite p-buffers with an elevated doping in the vicinity of the active layer considerably increase the operation voltage. Silicon carbide MESFETs utilizing composite buffers are reported.