Electrical and Photoelectric Characterization of Heterostructure FETS

摘要

This report presents experimental and theoretical studies on HeterostructureField Effect Transistors (HFETs). Included are dc, rf, and photoelectric measurements. Measurements on devices with very short gate length (200 nm) revealed that the hot electron effects are masked by parasitic effects, specifically source resistance. The hot electron effects were observed using de-embedding techniques. The rf studies revealed that the hot electron effects were not frequency dependant, in agreement with theoretical expectations. An attempt was made to evaluate the increase in electron temperature due to heating by the drain voltage. It was found that the rise in temperature for electrons emitted to the gate is approximately 100 deg C. A new photoelectric technique was developed to evaluate non-destructively fully fabricated HFETs. The technique is based on photoemission and conduction (PEC) studies. Intersubband transitions were observed and successfully identified. Furthermore, it was observed that the transistor amplified the photogenerated current due to hole storage effects.