Ronald D. Schrimpf

Radiation-induced charge trapping in thin Al/sub 2/O/sub 3//SiO/sub x/N/sub y//Si(100) gate dielectric stacks

We examine the total-dose radiation response of capacitors and transistors with stacked Al/sub 2/O/sub 3/ on oxynitride gate dielectrics with Al and poly-Si gates after irradiation with 10 keV X-rays. The midgap voltage shift increases monotonically with dose and depends strongly on both Al/sub 2/O/sub 3/ and SiO/sub x/N/sub y/ thickness. The thinnest dielectrics, of most interest to industry, are extremely hard to ionizing irradiation, exhibiting only /spl sim/50 mV of shift at a total dose of 10 Mrad(SiO/sub 2/) for the worst case bias condition. Oxygen anneals are found to improve the total dose radiation response by /spl sim/50% and induce a small amount of capacitance-voltage hysteresis. Al/sub 2/O/sub 3//SiO/sub x/N/sub y/ dielectrics which receive a /spl sim/1000/spl deg/C dopant activation anneal trap /spl sim/12% more of the initial charge than films annealed at 550/spl deg/C. Charge pumping measurements show that the interface trap density decreases with dose up to 500 krad(SiO/sub 2/). This surprising result is discussed with respect to hydrogen effects in alternative dielectric materials, and may be the result of radiation-induced hydrogen passivation of some of the near-interfacial defects in these gate dielectrics.

Analysis of the time-dependent turn-on mechanism for single-event burnout of n-channel power MOSFETs

For the first time, this paper investigates the time-dependent mechanisms involved in single-event burnout (SEB). SEB of power metal-oxide-semiconductor field-effect transistors (MOSFETs)is a catastrophic failure mechanism initiated by the passage of a heavy ion through the device structure. In previous work, analytical models have been developed to explain the regenerative feedback mechanism that induces second breakdown of the parasitic bipolar junction transistor (BJT). In this paper, a first order dynamic model is presented to lend insight into the turn-on of the parasitic BJT by the heavy ion.<<ETX>>