Study of Ga(0.47)In(0.53)As/Al(0.48)In(0.52)As for Very High Frequency Device Applications

摘要

AlInAs/GaInAs/InP Modulation Doped Field Effect Transistors are investigated for millimeter wave device applications. AlInAs/GaInAs/InP MODFETs with gate lengths varying from 1.0 micron to 0.1 micron have been successfully fabricated and characterized at DC and microwave frequencies. Measured unity current gain cutoff frequencies between 100-120 GHz and power gain cutoff frequencies between 220-250 GHz are obtained for 0.2 micron gate length MODFETs. Unity current gain cutoff frequencies between 140-150 GHz are measured for 0.1 micron gate length MODFETs. Short gate length effects are studied to understand transport mechanisms in the MODFETs in order to further improve performance. Excess gate current due to hot electron effects are observed in short gate MODFETs. The RF and DC output conductance characteristics are measured and analyzed. New structures including variations in buffer layer design, atomic planar doping profiles, strained layer structures and mismatched structures are investigated. Keywords: MODFET; Al; InAs/Ga, InAs/InP; Short gate; and Millimeter-wave. (RH)