Browsing by Author "Hu, Peter"

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28V high-linearity and rugged InGaP/GaAs power HBT
(2006)
Wang, Nanlei Larry
;
Ma, Wenlong
;
Xu, Sarah
;
Camargo, Edmar
;
Sun, Xiaopeng
This paper reports on the improvement of a previously developed InGaP/GaAs HBT for 24-28V linear power operation. The improvements achieved were: application of dynamic bias circuit which improves the ACLR under WCDMA modulation; modification of device technology improving ruggedness to sustain 10:1 VSWR at 30V collector bias under P1dB driving conditions and over 6 dB of gain compression; maintenance of lifetime and reliability simultaneously. Building blocks of HBT were strung together for higher power and good scaling of performance was achieved supporting the validity of the layout approach and the thermal design. Devices delivering P-1dB = 8W under CW conditions provided ACLR = -50 dBc at 8.5 dB back-off and 16% efficiency for WCDMA signal (PAR=8.7 dB) at 2.14 GHz. Lifetime test over 3000 hours was repeated for 28V bias and 0.05mA/um(2) current density at 315 degree C junction temperature. Therefore, the InGaP/GaAs HBT technology is mature now for the high linearity power amplification.
Reliability study of InGaP/GaAs HBT for 28V operation
(2006)
Chau, Frank Hin-Fai
;
Lin, Barry Jia-Fu
;
Chen, Yan
;
Kretschmar, Mark
;
Lee, Chien-Ping
This paper reports the device process and reliability aspects of a high voltage InGaP/GaAs HBT technology for 28V operation. The key differences and challenges from the material and process perspectives relative to the conventional low voltage HBT technology are first described. Long-term reliability tests performed at 28V bias voltage, 5.2kA/cm(2) current density and 310 degrees C junction temperature resulted in zero device failures after over 3600 hours of stress. Wafer-level reliability tests using extreme current stress conditions were used to force transistors to degrade in short time for quick checking of transistor integrity and process reliability. Transistor lifetimes were generally higher than those in conventional low voltage HBTs at similar junction temperatures. Combining with the previously reported ruggedness and linearity performance, the high voltage InGaP/GaAs HBT is a mature technology for use in the 28V high linearity power amplification.