Title :
Studies of the DC, low-frequency, and microwave characteristics of uniform and step-doped GaAs/AlGaAs HEMTs
Author :
Chau, Hin-Fai ; Pavlidis, Dimitris ; Cazaux, Jean-Louis ; Graffeuil, Jacques
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
fDate :
10/1/1989 12:00:00 AM
Abstract :
A theoretical and experimental study of step-doped HEMTs (high electron mobility transition) with lightly and heavily doped regions is presented. Threshold voltage control and sensitivity with respect to growth parameters and recessing etching, as well as design criteria, are investigated for these structures. A three-regime charge control model is used to predict their performance. Using the same semianalytical theory, which was validated with the help of a self-consistent analysis, both conventional and step-doped HEMTs with an i-layer are compared. 1-μm gate-length n-channel HEMTs with step-doped profile thicknesses of 25, 50, and 100 Å were fabricated and tested at low and high frequencies. The low-frequency noise can be controlled by the step thickness, and a noise analysis is presented. Cutoff frequencies of 16 to 18 GHz and maximum oscillation frequencies of 41 to 59 GHz were measured and correlated to the step thickness
Keywords :
III-V semiconductors; aluminium compounds; electron device noise; gallium arsenide; high electron mobility transistors; semiconductor device models; solid-state microwave devices; 1 micron; 16 to 18 GHz; 41 to 59 GHz; DC characteristics; GaAs-AlGaAs; LF characteristics; cutoff frequencies; growth parameters; heavily doped regions; low-frequency noise; maximum oscillation frequencies; microwave characteristics; n-channel HEMTs; noise analysis; recessing etching; semianalytical theory; step thickness; step-doped HEMTs; three-regime charge control model; threshold voltage control; Automatic testing; Cutoff frequency; Electron mobility; Etching; HEMTs; Low-frequency noise; MODFETs; Predictive models; Threshold voltage; Voltage control;
Journal_Title :
Electron Devices, IEEE Transactions on
