scholarly journals Study on Possible Double Peaks in Cutoff Frequency Characteristics of AlGaAs/GaAs HBTs by Energy Transport Simulation

VLSI Design ◽  
1998 ◽  
Vol 8 (1-4) ◽  
pp. 437-442
Author(s):  
T. Okada ◽  
K. Horio
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Energy Transport ◽  
Transport Model ◽  
Cutoff Frequency ◽  
Bipolar Transistors ◽  
Electron Velocity ◽  
Collector Current ◽  
Double Peak ◽  
Double Peaks ◽  
Energy Profiles

By using an energy transport model, we simulate cutoff frequency fT  versus collector current density IC characteristics of npn−n AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with various n−-collector thickness and n−-doping densities. It is found that the calculated fT  characteristics show double peak behavior when the n−- layer is thick enough and the n−-doping is high enough to allow existence of neutral n−- region. The mechanism of the double peak behavior is discussed by studying energy band diagrams, electron-energy profiles and electron-velocity profiles. Particularly, we discuss the origin of the second peak (at higher IC) which is not usually reported experimentally.

Study of The Transversal Electron Mobility in Heterojunction Bipolar Transistors with Strained SI1−x Gex-Base

1992 ◽  
Vol 281 ◽  
Author(s):  
J. Poortmans ◽  
M. Caymax ◽  
A. Van Ammel ◽  
M. Libezny ◽  
J. Nijs
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Electron Mobility ◽  
Doping Level ◽  
Theoretical Calculations ◽  
Bipolar Transistors ◽  
Effective Density ◽  
Collector Current ◽  
Strained Si ◽  
Strained Layers ◽  
B Doping

ABSTRACTThe effective transversal mobility of the minority carrier electrons in asymmetrically strained p-type Si1−x Gex -layers, grown on a Si (100) substrate, is studied as a function of boron doping concentration and Ge-content x. The experiments are based on the temperature dependence (290 to 400K) of the collector current enhancement of heterojunction bipolar transistors with a pseudomorphic Si1−x Gex-base. The interpretation of these results is based on new insights about the effective density of states in the valence band of these strained layers [1]. We will present first experimental evidence of the theoretical calculations in [1]. From this we will derive then the value of the NcNv -product for the strained Si1−x Gex-alloy. This allows to extract the ratio of the electron mobility in Si and strained Si1−xGex. We found an enhancement of the mobility when the B-doping level is around 1018 cm−3 and 0.08<x<0.16. At higher values of the Ge-content and the doping level, the enhancement is reduced again.

Simulation of Collector Current Distribution in Heterojunction Bipolar Transistors Using Newly Proposed Empirical Expression

1996 ◽  
Vol 35 (Part 1, No. 2A) ◽  
pp. 574-577
Author(s):  
Teruyuki Shimura ◽  
Masayuki Sakai ◽  
Manabu Kato ◽  
Sigekazu Izumi ◽  
Ryo Hattori ◽  
...  
Keyword(s):  
Current Distribution ◽  
Heterojunction Bipolar Transistors ◽  
Bipolar Transistors ◽  
Collector Current ◽  
Empirical Expression

High-Power Characteristics of GaN/InGaN Double Heterojunction Bipolar Transistors with a Regrown p-InGaN Base Layer

2003 ◽  
Vol 798 ◽  
Author(s):  
Toshiki Makimoto ◽  
Yoshiharu Yamauchi ◽  
Kazuhide Kumakura
Keyword(s):  
High Power ◽  
Heterojunction Bipolar Transistors ◽  
Bipolar Transistors ◽  
Base Layer ◽  
Collector Current ◽  
Power Characteristics ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Double Heterojunction ◽  
Extrinsic Base

ABSTRACTWe have investigated high-power characteristics of GaN/InGaN double heterojunction bipolar transistors on SiC substrates grown by metalorganic vapor phase epitaxy. The p-InGaN extrinsic base layers were regrown to improve ohmic characteristics of the base. Base-collector diodes showed low leakage current at their reverse bias voltages due to a wide bandgap of a GaN collector, resulting in a high-voltage transistor operation. A 90 μm × 50 μm device operated up to a collector-emitter voltage of 28 V and a collector current of 0.37 A in its common-emitter current-voltage characteristics at room temperature, which corresponds to a DC power of 10.4 W. A collector current density and a power density are as high as 8.2 kA/cm2 and 230 kW/cm2, respectively. These results show that nitride HBTs are promising for high-power electronic devices.

EXPERIMENTAL CHARACTERIZATION AND MODELING ANALYSIS ON NPN AlGaN/GaN HBT WITH HIGH IDEALITY FACTOR IN BOTH COLLECTOR AND BASE CURRENT

2012 ◽  
Vol 19 (04) ◽  
pp. 1250043
Author(s):  
SHIH-WEI TAN ◽  
SHIH-WEN LAI
Keyword(s):  
Schottky Diode ◽  
Heterojunction Bipolar Transistors ◽  
Ideality Factor ◽  
Equivalent Circuit Model ◽  
Bipolar Transistors ◽  
Base Layer ◽  
Collector Current ◽  
Base Current ◽  
Modeling Analysis ◽  
Good Agreement

Characterization and modeling analysis on both ideality factor of the collector current (η C ) and the base current (η B ) have higher than the excepted values of 1.0 and 2.0, respectively, for npn Al GaN/GaN heterojunction bipolar transistors (HBTs) have been reported. We employ the rapid thermal process annealing (RTP-annealing) to modify the base parasitical Schottky diode (called A-HBTs) after the as-deposited Ni/Au bilayers on the base layer for electrode with no annealing (called N-HBTs) to compare with each other. For a HBT operated in Gummel-plot configuration, experimental and modeling results indicate that the base parasitical Schottky diode (BPSD) causes the base current (I B ) and collector current (I C ) with high ideality factor and raise the base-emitter voltage (V BE ) to higher operation point, and therefore lead to more power consumption. Furthermore, the extended Ebers–Moll equivalent-circuit model together with the extracted device parameters provided simulated results that were in a good agreement with experimental ones.

A Novel GaAs Bipolar Transistor Structure with GaInP-Hole Injection Blocking Barrier

1991 ◽  
Vol 240 ◽  
Author(s):  
W. Pletschen ◽  
K. H. Bachem ◽  
T. Lauterbach
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gaas Layer ◽  
Bipolar Transistors ◽  
Hole Injection ◽  
Collector Current ◽  
Offset Voltage ◽  
Layer Structures ◽  
Current Densities ◽  
Output Characteristics ◽  
Base Doping

ABSTRACTGaAs bipolar transistors of different emitter types have been fabricated from MOCVD grown lattice matched Ga0.5In0.5 P/GaAs layer structures using carbon for heavy base doping (p=2×1019 cm−3). Besides conventional heterojunction bipolar transistors we also investigated tunneling emitter bipolar transistors having 2 and 5 nm thin GalnP layers between emitter and base, which act as a hole repelling potential barrier in the valence band. Current gains up to 115 have been obtained at collector current densities of 104 A/cm2 even for this heavy base doping. All devices show an almost ideal output characteristics with large Early voltage and small offset voltage. From the temperature dependence of the collector current a small effective conduction band barrier at the heterointerface is determined which hardly affects electron injection into the base.

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