Title :
Thermal performance of metamorphic double heterojunction bipolar transistors with InP and InAlP buffer layers
Author :
Kim, Y.M. ; Dahlstrom, M. ; Rodwell, M.J.W. ; Gossard, A.C.
Author_Institution :
Dept. of Electr. & Comput. Eng., California Univ., Santa Barbara, CA, USA
Abstract :
InP-based double heterojunction bipolar transistors (DHBT) are a key technology for high-speed optical fiber transmission. InP substrates are expensive and are not available in as large sizes as GaAs substrates. Moreover, InP substrates are fragile and are easily broken in fabrication. This motivates development of metamorphic InP DHBT (MDHBT) on GaAs. Thermal performance is of critical importance, as high speed DHBTs must operate at emitter power densities exceeding 250 kW/cm/sup 2/. In the case of MDHBTs, thermal resistance is dominated by the poor thermal conductivity of the thick (1-1.5 μm) metamorphic buffer layer lying immediately below the collector. Here we compare the thermal characteristics of MDHBTs grown on InP and InAlP buffer layers to those of lattice-matched devices. In the case of InP buffer layers and narrow emitter geometries, MDHBT thermal resistance is comparable to that of lattice-matched HBTs. A low 32 °C junction-ambient temperature rise is obtained in a device operating at 235 kW/cm/sup 2/.
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; indium compounds; thermal conductivity; thermal resistance; 1 to 1.5 micron; GaAs; GaAs substrates; InAlP; InAlP buffer layers; InP; InP buffer layers; double heterojunction bipolar transistors; emitter power densities; metamorphic InP DHBT; metamorphic buffer layer; narrow emitter geometries; thermal conductivity; thermal performance; thermal resistance; Buffer layers; Double heterojunction bipolar transistors; Gallium arsenide; Geometry; Indium phosphide; Optical device fabrication; Optical fibers; Temperature; Thermal conductivity; Thermal resistance;
Conference_Titel :
Device Research Conference, 2002. 60th DRC. Conference Digest
Conference_Location :
Santa Barbara, CA, USA
Print_ISBN :
0-7803-7317-0
DOI :
10.1109/DRC.2002.1029579
