Title :
Influence of quantum-well width on device performance of Al0.30Ga0.70As/In0.25Ga0.75 As (on GaAs) MODFETs
Author :
Nguyen, Loi D. ; Radulescu, David C. ; Foisy, Mark C. ; Tasker, Paul J. ; Eastman, Lester F.
Author_Institution :
Sch. of Electr. Eng., Cornell Univ., Ithaca, NY, USA
fDate :
5/1/1989 12:00:00 AM
Abstract :
An experimental study in which the quantum well width (W) is varied from 45 to 200 Å is discussed. Optimum device performance was observed at a well width of 120 Å. The 0.2-μm×130-μm devices with 120-Å quantum-well width typically exhibit a maximum channel current density of 550 mA/mm, peak transconductance of 550 mS/mm, and peak current gain cutoff frequency ( fT) of 122 GHz. These results have been further improved in subsequent fabrications employing a trilevel-resist mushroom-gate process. The 0.2-μm×50-μm devices with mushroom gate exhibit a peak transconductance of 640 mS/mm, peak f T of 100 GHz, and best power gains cutoff frequency in excess of 200 GHz. These results are among the best ever reported for GaAs-based FETs and are attributed to the high two-dimensional electron gas (2DEG) sheet density, good low-field mobility, low ohmic contact, and the optimized mushroom gate process
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; high electron mobility transistors; indium compounds; semiconductor quantum wells; solid-state microwave devices; 100 GHz; 1220 GHz; 2DEG sheet density; 45 to 200 Å; 45 to 200 angstroms; 550 mS; 640 mS; Al0.30Ga0.70As-In0.25Ga0.75 As-GaAs; GaAs; MM-wave applications; channel current density; current gain cutoff frequency; device performance; low ohmic contact; low-field mobility; quantum-well width; threshold frequency; transconductance; trilevel-resist mushroom-gate process; FETs; Fabrication; Gallium arsenide; HEMTs; Indium; Lattices; MODFETs; Nanofabrication; Quantum well devices; Transconductance;
Journal_Title :
Electron Devices, IEEE Transactions on
