Characterization of high performance inverted delta-modulation-doped (IDMD) GaAs/InGaAs pseudomorphic heterostructure FET´s

An inverted delta-modulation-doped (IDMD) GaAs/InGaAs pseudomorphic heterostructure grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) is demonstrated and discussed. The respective influences of delta-doping period and spacer thickness on the sheet carrier densities and mobilities are investigated. For a 1.5×80 μm² gate, a reverse leakage current smaller than 10 μA/mm (at -6.5 V), a drain-source breakdown voltage as high as 14.5 V, a maximum drain saturation current as high as 790 mA/mm, a maximum extrinsic transconductance as high as 250 mS/mm, a very broad gate voltage range of 3 V, and an electron saturation velocity up to 2.4×10⁷ cm/s, are obtained at room temperature. A simple theoretical simulation on the IDMD structure is also compared with the experimental results