Doping optimizations for InGaAs/InP composite channel HEMTs

Abstract

InGaAs/InP composite channel HEMTs are good candidates for electro-absorption modulator driver applications where both high speed and high breakdown voltage are required. For other applications – input stage of a pin-HEMT receiver for example – high cutoff frequency must meet with low leakage current. This calls for low delta-doped or undoped barrier material which is not easily compatible with high speed and high drain current. To achieve simultaneously all these criteria, a new HEMT heterostructure called here TC-HEMT (for triple channel-HEMT) has been investigated. Different HEMT heterostructures have been grown by LP-MOVPE for comparison. In this study, Hall mobilities and sheet carrier densities at 300 K have been measured for each structure and for different delta-doping level and spacer thickness. Finally, we compare static and dynamic characteristics measured on transistors near the Hall patterns.