Title :
0.15 mu m gate-length double recess pseudomorphic HEMT with f/sub max/ of 350 GHz
Author :
Lester, L.F. ; Smith, P.M. ; Ho, P. ; Chao, P.C. ; Tiberio, R.C. ; Duh, K.H.G. ; Wolf, E.D.
Author_Institution :
Sch. of Electr. Eng., Cornell Univ., Ithaca, NY, USA
Abstract :
The relative importance of f/sub t/ and f/sub max/ in millimeter-wave evaluation is discussed. Also presented is a study of the variation of C/sub gs/ (input capacitance), C/sub gd/ (gate-drain feedback capacitance), g/sub m/ (peak transconductance), and g/sub o/ (output conductance) with the distance, L/sub gd/, between the metal edge and the n/sup +/ cap layer on the drain side of the device in ultrashort-gate-length HEMT (high-electron-mobility transistors). For this study, a 0.15- mu m-gate-length, double-recess pseudomorphic HEMT was fabricated that exhibits a maximum frequency of oscillation, f/sub max/, of 350 GHz. This value is the highest f/sub max/ reported for any transistor. A very high C/sub gs//C/sub gd/ of 76 and a large voltage gain, g/sub m//g/sub o/ of 75 are observed in the device. These exceptional results are attained primarily by increasing L/sub gd/ to 2.3 times the gate length.<>
Keywords :
high electron mobility transistors; solid-state microwave devices; 0.15 micron; 350 GHz; MM-wave device; double-recess pseudomorphic HEMT; gate-drain feedback capacitance; gate-length; high-electron-mobility transistors; input capacitance; maximum frequency of oscillation; metal edge to n/sup +/ cap layer distance; output conductance; peak transconductance; voltage gain; Bonding; Capacitance; Equivalent circuits; FETs; HEMTs; Lithography; Millimeter wave circuits; PHEMTs; Radio frequency; Resists;
Conference_Titel :
Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International
Conference_Location :
San Francisco, CA, USA
DOI :
10.1109/IEDM.1988.32782
