A 4H-SiC BJT with an Epitaxially Regrown Extrinsic Base Layer

2005 ◽  
Vol 483-485 ◽  
pp. 905-908 ◽  
Author(s):  
Erik Danielsson ◽  
Martin Domeij ◽  
Hyung Seok Lee ◽  
Carl Mikael Zetterling ◽  
Mikael Östling ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Breakdown Voltage ◽  
Ohmic Contact ◽  
Base Layer ◽  
Current Gain ◽  
Epitaxial Regrowth ◽  
Extrinsic Base ◽  
Emitter Junction

4H-SiC BJTs were fabricated using epitaxial regrowth instead of ion implantation to form a highly doped extrinsic base layer necessary for a good base ohmic contact. A remaining p+ regrowth spacer at the edge of the base-emitter junction is proposed to explain a low current gain of 6 for the BJTs. A breakdown voltage of 1000 V was obtained for devices with Al implanted JTE.

Implantation-Free Low On-Resistance 4H-SiC BJTs with Common-Emitter Current Gain of 50 and High Blocking Capability

2009 ◽  
Vol 615-617 ◽  
pp. 833-836 ◽  
Author(s):  
Reza Ghandi ◽  
Hyung Seok Lee ◽  
Martin Domeij ◽  
Benedetto Buono ◽  
Carl Mikael Zetterling ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Breakdown Voltage ◽  
Life Time ◽  
Base Layer ◽  
Current Gain ◽  
Large Area ◽  
Fully Depleted ◽  
Dopant Activation ◽  
Emitter Current ◽  
Activation Annealing

In this study, high voltage blocking (2.7 kV) implantation-free SiC Bipolar Junction Transistors with low on-state resistance (12 mΩ•cm2) and high common-emitter current gain of 50 have been fabricated. A graded base doping was implemented to provide a low resistive ohmic contact to the epitaxial base. This design features a fully depleted base layer close to the breakdown voltage providing an efficient epitaxial JTE without ion implantation. Eliminating all ion implantation steps in this approach is beneficial for avoiding high temperature dopant activation annealing and for avoiding generation of life-time killing defects that reduces the current gain. Also in this process large area transistors showed common-emitter current gain of 38 and open-base breakdown voltage of 2 kV.

Current Gain Dependence on Emitter Width in 4H-SiC BJTs

2006 ◽  
Vol 527-529 ◽  
pp. 1425-1428 ◽  
Author(s):  
Martin Domeij ◽  
Hyung Seok Lee ◽  
Carl Mikael Zetterling ◽  
Mikael Östling ◽  
Adolf Schöner
Keyword(s):  
Size Effect ◽  
Epitaxial Growth ◽  
Breakdown Voltage ◽  
Significant Influence ◽  
Surface Recombination ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Maximum Current ◽  
Emitter Junction ◽  
Good Agreement

This paper reports the fabrication of epitaxial 4H-SiC bipolar junction transistors (BJTs) with a maximum current gain β=64 and a breakdown voltage of 1100 V. The high β value is attributed to high material quality obtained after a continuous epitaxial growth of the base-emitter junction. The current gain of the BJTs increases with increasing emitter width indicating a significant influence of surface recombination. This “emitter-size” effect is in good agreement with device simulations including recombination in interface states at the etched termination of the baseemitter junction.

scholarly journals Investigation of the Breakdown Voltage in High Voltage 4H-SiC BJT with Respect to Oxide and Interface Charges

2015 ◽  
Vol 821-823 ◽  
pp. 834-837 ◽  
Author(s):  
Arash Salemi ◽  
Hossein Elahipanah ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Ion Implantation ◽  
Breakdown Voltage ◽  
Surface Passivation ◽  
Base Layer ◽  
Interface Trap Density ◽  
Interface Traps ◽  
Bipolar Junction Transistor ◽  
Fixed Charges ◽  
Interface Charges ◽  
Junction Transistor

Ion implantation in silicon carbide (SiC) induces defects during the process. Implantation free processing can eliminate these problems. The junction termination extension (JTE) can also be formed without ion implantation in SiC bipolar junction transistor (BJT) using a well-controlled etching into the epitaxial base layer. The fixed charges at the SiC/SiO2 interface modify the effective dose of the JTEs, leakage current, and breakdown voltage. In this paper the influence of fixed charges (positive and negative) and also interface trap density at the SiC/SiO2 interface on the breakdown voltage in 4.5 kV 4H-SiC non-ion implanted BJT have been simulated. SiO2 as a surface passivation layer including interface traps and fixed charges has been considered in the analysis. Simulation result shows that the fixed charges influence the breakdown voltage significantly more than the interface traps. It also shows that the positive fixed charges reduce the breakdown voltage more than the negative fixed charges. The combination of interface traps and fixed charges must be considered when optimizing the breakdown voltage.

A High Current Gain 4H-SiC BJT of Novel Epitaxial Passivation Structure

2018 ◽  
Vol 924 ◽  
pp. 625-628
Author(s):  
You Run Zhang ◽  
Wen Wang ◽  
Ming Ye Li ◽  
Fei Guo ◽  
Jun Tao Li ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Surface Recombination ◽  
High Gain ◽  
Base Layer ◽  
Current Gain ◽  
The Novel ◽  
High Current ◽  
Novel Structure ◽  
P Type ◽  
Extrinsic Base

This paper proposes a novel high-gain 4H-SiC BJT structure with a p-type epitaxial layer on top of the extrinsic base layer. The current gain of the novel structure is improved by 140% compared with the conventional one by the simulator tool with the number of reasonable interface traps, which could be ascribed to the epitaxial layer to reduce the surface recombination in the extrinsic base. The process to fabricate this structure is also proposed in the paper.

High Current Gain Triple Ion Implanted 4H-SiC BJT

2009 ◽  
Vol 1195 ◽  
Author(s):  
Taku Tajima ◽  
Tadashi Nakamura ◽  
Yuki Watabe ◽  
Masataka Satoh ◽  
Tohru Nakamura
Keyword(s):  
Ion Implantation ◽  
Current Gain ◽  
High Current ◽  
Extrinsic Base ◽  
Triple Ion ◽  
Ion Implanted

AbstractWe investigated triple ion implanted 4H-SiC BJT with etched extrinsic base regions. To remove the defects induced by ion implantation between emitter and base regions, the characteristics of triple ion implanted 4H-SiC BJT were significantly improved. Maximum common current gain was improved from 1.7 to 7.5.

Area-Optimized JTE for 4.5 kV Non Ion-Implanted 4H-SiC BJT

2013 ◽  
Vol 740-742 ◽  
pp. 974-977 ◽  
Author(s):  
Arash Salemi ◽  
Hossein Elahipanah ◽  
Benedetto Buono ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Electric Field ◽  
Ion Implantation ◽  
Field Distribution ◽  
Breakdown Voltage ◽  
Contact Area ◽  
Electric Field Distribution ◽  
Current Gain ◽  
High Current ◽  
High Breakdown Voltage ◽  
Base Contact

Non ion-implantation mesa etched 4H-SiC BJT with three-zone JTE of optimized lengths and doses (descending sequences) has been simulated. This design presents an efficient electric field distribution along the device. The device area has been optimized and considerably reduced. As a result of this comprehensive optimization, a high breakdown voltage and high current gain have been achieved; meanwhile the device area with a constant emitter and base contact area has been reduced by about 30%.

High Breakdown Voltage GaN HEMT Device Fabricated on Self-Standing GaN Substrate

2013 ◽  
Vol 347-350 ◽  
pp. 1535-1539
Author(s):  
Jian Jun Zhou ◽  
Liang Li ◽  
Hai Yan Lu ◽  
Ceng Kong ◽  
Yue Chan Kong ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Breakdown Voltage ◽  
Oxygen Plasma ◽  
Cutoff Frequency ◽  
Chemical Vapor ◽  
Current Gain ◽  
Organic Chemical ◽  
Oxygen Plasma Treatment ◽  
Gan Hemt ◽  
High Breakdown Voltage

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

Solid phase epitaxial regrowth of Si1−xGex/Si strained‐layer structures amorphized by ion implantation

1989 ◽  
Vol 54 (1) ◽  
pp. 42-44 ◽  
Author(s):  
B. T. Chilton ◽  
B. J. Robinson ◽  
D. A. Thompson ◽  
T. E. Jackman ◽  
J.‐M. Baribeau
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Strained Layer ◽  
Epitaxial Regrowth ◽  
Layer Structures

Current Gain of 4H-SiC Bipolar Transistors Including the Effect of Interface States

2005 ◽  
Vol 483-485 ◽  
pp. 889-892 ◽  
Author(s):  
Martin Domeij ◽  
Erik Danielsson ◽  
Hyung Seok Lee ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Side Wall ◽  
Interface States ◽  
Bipolar Transistors ◽  
Current Gain ◽  
Poor Agreement ◽  
Collector Current ◽  
Bandgap Narrowing ◽  
Pulsed Measurements ◽  
Emitter Junction ◽  
Constant Distribution

The current gain (b) of 4H-SiC BJTs as function of collector current (IC) has been investigated by DC and pulsed measurements and by device simulations. A measured monotonic increase of b with IC agrees well with simulations using a constant distribution of interface states at the 4H-SiC/SiO2 interface along the etched side-wall of the base-emitter junction. Simulations using only bulk recombination, on the other hand, are in poor agreement with the measurements. The interface states degrade the simulated current gain by combined effects of localized recombination and trapped charge that influence the surface potential. Additionally, bandgap narrowing has a significant impact by reducing the peak current gain by about 50 % in simulations.

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