Integrated circuit design considerations for spacecraft VLSI implemented in standard CMOS processes.

摘要

In this dissertation I will examine issues concerning the use of custom Application Specific Integrated Circuits (ASIC)s, fabricated at commercial foundries, for use in spacecraft. I will examine this subject from the fabrication, device, circuit and system level.; I begin with an overview of integrated circuit fabrication and post processing technology used to physically alter the circuit and enhance its electrical performance. I examine the MOS transistor and its variant the Floating-Gate MOS transistor from a device perspective. I discuss a model, derived from the electrostatics of the MOS structure, that is continuous over the entire region of operation while maintaining a small set of physical parameters. Secondly, the operation of the Floating-Gate MOSFET, a device finding increasing usage in adaptive systems, will be presented. The model is then expanded to include the effects of exposure to ionizing radiation on MOSFETs.; From a circuit perspective, I will examine the issue of power and energy usage in a digital system. The current-mode design approach will be reviewed as an introduction to Current-Mode-Differential-Logic, a low energy logic family. I will discuss Floating-Gate-Logic, an application of floating-gate transistors to solve the low-power problem by adjusting device thresholds.; The second half of the dissertation will be focused on radiation effects in MOS devices. I begin by describing the, rather unpleasant, environment that spacecraft operate in. I continue with a discussion on two main effects of radiation exposure that engineers need to contend with, radiation induced latchup and total-dose exposure. I will provide results from different experiments designed to evaluate a commercial CMOS process's usability for a space application. Finally I describe an application that utilizes the negative effects of radiation on floating-gate MOS devices, an integrated, electronic micro-dosimeter.