A Pulsed-measurement Instrument for Device Testing

摘要

For many discrete GaAs FETs, high electron mobility transistors (HEMT) and integrated devices in GaAs MMICs, the large-signal IV characteristics of the device at RF, microwave or mm-wave frequencies are very different from the DC characteristics. This phenomenon, which is known as dispersion, may also occur in some HEMTs used in other materials systems as well as heterojunc-tion bipolar transistors (HBT) and silicon bipolar junction transistors (BJT). In GaAs FETs and HEMTs, dispersion may occur due to charge changes in deep levels (or traps) or from self-heating during electrical operation. In HBTs and BJTs, self-heating is the main mechanism. A recently developed pulsed-measurement instrument provides the means to measure the RF large-signal and DC characteristics of all these device types.