SILICON-CONTROLLED AND BIDIRECTIONAL SWITCHES - CHARACTERIZATION AND RADIATION EFFECTS

Gamma-irradiation effects on the electrical parameters of the DIode AC switch (DIAC; PH137 500) and Silicon Controlled Rectifier (SCR; 2N444 4) devices have been studied in detail, where gamma-dose up to 137 x 1 0(6) rad was found to cause a serious permanent damage on their electr ical characteristics. A pronounced increase in the break-over voltage (from 31.5 V to 35 V), holding-current (from 13 mA to 53 mA) and holdi ng voltage (from 22 V to 32 V) of the DIAC is noticed. Besides, a seve re decrease in the dynamic break-over voltage range (from 10 V to 2.5 V) and negative resistance (from -750 ohm to -168 ohm) is also observe d. Exposing the SCRs to gamma-radiation similarly causes their turn-on voltage and forward voltage drop values to increase from 0.80 V to 2. 8 V and from 1.40 V to 4.50 V respectively. Additionally, the holding current increases to 18 mA although its initial value is 3.5 mA. For t he two devices, the Linear dependence and high sensitivity of their el ectrical parameters to gamma-dose suggest the application of such devi ces in the field of radiation dosimetry.