DC and AC characteristics of AL/sub 0.25/Ga/sub 0.75/As/GaAs quantum-well delta-doped channel FET grown by LP-MOCVD

Abstract

Al/sub 0.25/Ga/sub 0.75/As/GaAs quantum well delta-doped channel FETs (QWDFETs) have been successfully fabricated by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The FETs with a gate dimension of 1.8 mu m*100 mu m had a maximum extrinsic transconductance of 190 mS/mm and a maximum current density of 425 mA/mm. The device showed extremely broad transconductances around its peak. The S-parameter measurements indicated that the current gain and power gain cutoff frequencies of the device were 7 and 15 GHz, respectively. The transconductance versus gate voltage profiles showed a plateau region through a range of 1.7 V supporting spatial confinement of the electrons. These values are among the best reported for delta-doped GaAs-based FETs with a similar device geometry.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>