Measurement of SOI MOSFET I-V characteristics without self-heating

In addition to offering advantages, the isolation provided by silicon-on-insulator (SOI) MOSFET device technology also poses some problems. Because the channel is thermally insulated from the substrate, the channel temperature can differ from its surroundings, and current through the channel can cause self-heating. Because the channel is isolated, the floating body can cause the kink effect. Self-heating is thought to occur for power-on times longer than 100 ns, and the time constant for the kink effect depends on the silicon film quality. Thus static, DC, measurements of output characteristics may not reveal the dynamic characteristics of a rapidly switching device in a digital circuit. This paper demonstrates, for the first time, a simple and direct method of measuring I-V curves on a nanosecond time scale, thus avoiding the self-heating problem. The method has been implemented in an automated system.