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Author Hsu, Shuo-Hung
Title Microwave heterostructure device characterization and modeling for their high-power and low-noise properties
book jacket
Descript 224 p
Note Source: Dissertation Abstracts International, Volume: 64-02, Section: B, page: 0872
Chair: Dimitris Pavlidis
Thesis (Ph.D.)--University of Michigan, 2003
This dissertation focuses on characterization and modeling of novel heterostructure devices as regards their high-power and low-noise properties for microwave front-end circuit applications. Recent advances in heterostructure devices such as heterojunction bipolar transistors (HBTs) and modulation-doped field effect transistors (MODFETs) are the major driving force for developing novel microwave circuits as well as communication systems. Characterizing and modeling of these devices allow us to understand physical principles and limitations of the devices and provide feedback to improve the design of device materials and structures. In addition, using established device models, one can design circuits and systems with greatly reduced iteration cycles
This study investigates a wide variety of novel heterostructure microwave devices. Thermally-stable-cascode (TSC) AlGaAs/GaAS HBTs with a 100 mum separation between the common-emitter and common-base stages demonstrate significantly reduced thermal effects. Highly nonlinear InAlAs/InGaAs PNP HBTs present distributed thermal time constants (RTH1 ∼ 580 K/W, RTH2 ∼ 710 K/W; CTH1 ∼ 0.4 ns W/K, CTH2 ∼ 0.1 mus W/K). AlGaN/GaN MODFETs show increased PAE ∼ 12% with harmonic tuning. Typical IMD3 is ∼29 dBm (f0 = 5 GHz) and the dominant nonlinear source is the transconductance. InP/InGaAs NPN HBTs demonstrate excellent noise figure under low power consumption (Fmin = 1.51 dB under PDC = 1.6 mW at 10 GHz). Low gate leakage current ( IG ∼ 1 to 4 muA under VDS = 0 to 15 V) is a key factor for the observed low-noise performance in AlGaN/GaN MODFETs. Low-frequency noise studies reveal that the dominant noise source in NPN/PNP InP HBTs is the exposed emitter periphery, while the low-frequency noise stemming from the 2DEG and buffer layer in AlGaN/GaN MODFETs. Trap-related studies suggest that the pronounced output resistance dispersion is due to traps located in the drain-gate area. The observed current instability is no permanent damage and can be recovered by UV light
In addition, systematic approaches based on various measurement techniques are proposed to develop equivalent circuit models. Device model parameters and nonidealities such as the thermal effect and the dispersion effect can be extracted. The approaches introduced in this study can be applied to various semiconductor devices to obtain a better understanding of modern heterostructure devices and to achieve high-power and low-noise performance for microwave circuit applications
School code: 0127
Host Item Dissertation Abstracts International 64-02B
Subject Engineering, Electronics and Electrical
Alt Author University of Michigan
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