Wafer-fused n-AlGaAs/p-GaAs/n-GaN Heterojunction Bipolar Transistor with uid-GaAs Base-Collector Setback

2003 ◽  
Vol 798 ◽  
Author(s):  
Sarah Estrada ◽  
James Champlain ◽  
Chad Wang ◽  
Andreas Stonas ◽  
Larry Coldren ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
High Mobility ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Output Current ◽  
Wafer Fusion ◽  
Conduction Band Offset ◽  
Direct Wafer Bonding ◽  
High Degree

ABSTRACTRecently we reported the first AlGaAs-GaAs-GaN heterojunction bipolar transistor (HBT), a device that potentially combines the high-breakdown voltage of an n-GaN collector with the high mobility of an AlGaAs-GaAs emitter-base. Because of the high degree of lattice mismatch between GaAs (lattice constant of 5.65A) and GaN (3.19A), we formed these devices through wafer fusion, also called direct wafer bonding. Measurements on the first generations of wafer fused HBTs revealed good current modulation, with modest output current (0.83 KA/cm2) and a current gain of 1.2. Limitations to the current gain may be related to traps and defects introduced by the fusion process, or may be a consequence of the natural conduction band offset between GaAs and GaN, which is not well known. This paper describes our new HBT structure that included a thin (20nm) uid-GaAs base-collector “setback” layer. The setback layer shifted the fused GaAs-GaN interface slightly into the collector. This new HBT structure also incorporated a reduced base thickness of 100 nm. HBTs with setback layers demonstrate increased output current (1.7 KA/cm2) and increased current gain (1.9).

The First Wafer-fused AlGaAs-GaAs-GaN Heterojunction Bipolar Transistor

2002 ◽  
Vol 743 ◽  
Author(s):  
Sarah Estrada ◽  
Andreas Stonas ◽  
Andrew Huntington ◽  
Huili Xing ◽  
Larry Coldren ◽  
...  
Keyword(s):  
High Mobility ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Fusion Temperature ◽  
Device Structure ◽  
Wafer Fusion ◽  
Current Voltage ◽  
Diffusion Effects ◽  
Current Voltage Characteristics

ABSTRACTWe describe the use of wafer fusion to form a heterojunction bipolar transistor (HBT), with an AlGaAs-GaAs emitter-base fused to a GaN collector. In this way, we hope to make use of both the high breakdown voltage of the GaN and the high mobility of the technologically more mature GaAs-based materials. This paper reports the first dc device characteristics of a wafer-fused transistor, and demonstrates the potential of wafer fusion for forming electronically active, lattice-mismatched heterojunctions. Devices utilized a thick base (0.15um) and exhibited limited common-emitter current gain (0.2–0.5) at an output current density of ∼100A/cm2. Devices were operated to VCE greater than 20V, with a low VCE offset (1V). Improvements in both device structure and wafer fusion conditions should provide further improvements in HBT performance. The HBT was wafer-fused at 750°C for one hour. Current-voltage characteristics of wafer-fused p-GaAs/n-GaN diodes suggest that the fusion temperature could be reduced to 500°C. Such a reduction in process temperature should mitigate detrimental diffusion effects in future HBTs.

scholarly journals Non-Graded Base Si/Ge Heterojunction Transistor

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Sam Mil'shtein ◽  
Harsha Purushothama Dombala ◽  
Oliver A Kia ◽  
Mukhammaddin Zinaddinov
Keyword(s):  
Wireless Communication ◽  
Power Amplifiers ◽  
Communication Systems ◽  
Carrier Transport ◽  
Lattice Mismatch ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Buffer Layers ◽  
Current Gain ◽  
Wide Range

<strong>Innovation of Heterojunction Bipolar Transistor (HBT) technology is a major game changer in wireless communication, power amplifiers and other major fields of electronics. HBTs play a vital role in extending the advantages of silicon bipolar transistors to significantly higher levels. Research on HBT is focused on reducing cost and improving reliability.  These transistors have a wide range of applications namely, digital-to-analog converters, logarithmic amplifiers, RF chip sets for CDMA wireless communication systems, and power amplifiers for cellular communications. Our study focuses on utilizing the high mobility of pure Ge instead of often-used graded Ge base. Non-grtaded Ge base enhanses carrier transport which in turn increases the gain and cut-off frequency of the HBT. We have developed a high frequency, high current gain, high power gain and less noisy heterojunction bipolar transistor operating above 100GHz frequency. Lattice mismatch at emitter and collector junctions is compensated by inserting SiGe buffer layers. ATLAS TCAD - SILVACO software is used for modelling of this novel device.</strong>

GaInP Selective Area Epitaxy for Heterojunction Bipolar Transistor Applications

1996 ◽  
Vol 448 ◽  
Author(s):  
S. H. PARK ◽  
S.-L. FU ◽  
P. K. L. YU ◽  
P. M. ASBECK
Keyword(s):  
Light Field ◽  
Defect Density ◽  
Forward Bias ◽  
Dark Field ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Selective Area Epitaxy ◽  
Metal Base ◽  
Selective Area

AbstractA study of selective area epitaxy (SAE) of GalnP lattice matched to GaAs is presented. The selectively regrown GaInP is used as the emitter of a novel heterojunction bipolar transistor (HBT) device structure. Successful SAE of GalnP on both dark field (mostly covered) and light field (mostly open) SiO2 masks is compared. To characterize the critical regrown heterojunction, diodes and HBTs were fabricated and measured. It is found that a pre-growth pause of either TEGa or PH3 results in forward bias characteristics with low leakage and an ideality factor of ~1.25, indicating low interfacial defect density. Non-self aligned regrown emitter HBTs grown with a dark field mask scheme have been fabricated. Devices with an emitter area of 3x12 μm exhibit small signal current gain up to 80 with an fT and fMAX of 22 GHz and 18 GHz, respectively. To further improve the performance of these devices, a structure with a self-aligned refractory metal base contact and light field regrowth is proposed.

Correlation between photoreflectance signal intensity and current gain of InP/InGaAs heterojunction bipolar transistor structures

2000 ◽  
Vol 88 (3) ◽  
pp. 1600-1605 ◽  
Author(s):  
Hiroki Sugiyama ◽  
Noriyuki Watanabe ◽  
Kazuo Watanabe ◽  
Takashi Kobayashi ◽  
Kazumi Wada
Keyword(s):  
Signal Intensity ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain

Current Gain of an AlGaN/GaN Heterojunction Bipolar Transistor

2001 ◽  
Vol 680 ◽  
Author(s):  
Yumin Zhang ◽  
P. Paul Ruden
Keyword(s):  
Electron Transport ◽  
Hybrid Model ◽  
Carrier Transport ◽  
Effective Field ◽  
Structure Design ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Design Parameters ◽  
Collector Current

ABSTRACTA novel hybrid model and simulation results for an advanced, graded base AlGaN/GaN heterojunction bipolar transistor structure are presented. The base of the n-p-n HBT examined has two parts, a linearly graded AlGaN layer on the emitter side and a heavily p-doped GaN layer on the collector side. In the hybrid model developed here the potential profile is first calculated self-consistently in the biased state taking into account ionized impurity charges, polarization charges, and majority carrier charges. The minority carrier transport is examined subsequently. Injection of electrons from the emitter is modeled as a thermionic emission process. The minority electron transport process in the graded region is drift-dominated due to the large built-in effective field strength. In the low-field GaN layer of the base, electron transport is assumed to be diffusion-dominated. High-level injection effects are modeled in the framework of the Gummel-Poon model. Example structure design parameters are presented and it is found that the calculated current gain can be greater than 25, with a collector current density of 104A/cm2.

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