Investigation on Transient Ionizing Radiation Effects in a 4-Mb SRAM With Dual Supply Voltages

The impact of transient ionizing radiation effects on a 4-Mb static random access memory (SRAM) circuit which has an input–output (IO) supply voltage and a core supply voltage was studied. The experimental results indicate that a longer time is required to restore minimal operating voltage for core supply voltage. Based on the 180-nm bulk CMOS technology, 3-D mode numerical simulations with technology computer-aided design (TCAD) show that the parasitic bipolar effect plays a significant role in discrepancy in the recovery process between supply voltages. This effect will be discussed in depth in this article, and the simulation results illustrate that the n-well contact has a great impact on the operation mode of parasitic bipolar. Meanwhile, the supply voltage disturbance mitigation methods are presented through improving power supply voltage and placing more n-well contacts.