Latch-Up Detection and Cancellation in CMOS VLSI Circuits

Abstract : This report looks at the issues involved in designing integrated circuits in bulk-CMOS processes for radiation environments. First, the report describes how radiation can cause transistor threshold to change and leakage currents to increase, and how these effects are mitigated in high-density VLSI processes. Secondly, it describes how radiation can activate parasitic structures endemic to bulk-CMOS processes, causing damaging effect called latch-up. Thirdly, the report describes how latch-up can be detected in an active circuit and cancelled before damage can occur - this is accompanied by successful experimental results with laser induced latch-up. Fourthly, it describes other integrated circuit fabrication technologies, which are naturally immune to latch-up. Finally, the report concludes with recommendations regarding further research that would be needed to validate the concept of bulk-CMOS integrated circuits in radiation environments.