Effects of Parasitic Region in SiC Bipolar Junction Transistors on Forced Current Gain

2018 ◽  
Vol 924 ◽  
pp. 629-632 ◽  
Author(s):  
Satoshi Asada ◽  
Jun Suda ◽  
Tsunenobu Kimoto
Keyword(s):  
Active Area ◽  
Hole Injection ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Collector Current ◽  
Spreading Resistance ◽  
Current Spreading ◽  
Intrinsic Region ◽  
Device Structures ◽  
Tcad Simulation

Effects of a parasitic region in SiC BJTs on conductivity modulation and a forced current gain (βF) were investigated by using TCAD simulation with various device structures. By introducing an Al+-implanted region below the base parasitic region, βF can be improved because the implanted region can reduce the base spreading resistance, leading to alleviation of debiasing effect. βF in devices with various parasitic areas, whose base spreading resistances were reduced by the Al+-implantation, were compared. We found that βF can be enhanced by expanding the parasitic area if the base spreading resistance is sufficiently reduced. The higher βF is attributed to an expanded conductivity-modulated region. The collector current spreading in the collector layer and the hole injection from the parasitic region as well as from the intrinsic region can play a role to evoke the conductivity modulation. Thus, the larger parasitic region can expand the conductivity-modulated region, resulting in expansion of an active area and the enhancement of βF.

1000 V, 30 A SiC Bipolar Junction Transistors and Integrated Darlington Pairs

2005 ◽  
Vol 483-485 ◽  
pp. 901-904 ◽  
Author(s):  
Sumi Krishnaswami ◽  
Anant K. Agarwal ◽  
Craig Capell ◽  
Jim Richmond ◽  
Sei Hyung Ryu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Voltage Drop ◽  
Active Area ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Collector Current ◽  
Bipolar Junction Transistor ◽  
Forward Voltage Drop ◽  
Junction Transistor ◽  
A Current

1000 V Bipolar Junction Transistor and integrated Darlington pairs with high current gain have been developed in 4H-SiC. The 3.38 mm x 3.38 mm BJT devices with an active area of 3 mm x 3 mm showed a forward on-current of 30 A, which corresponds to a current density of 333 A/cm2, at a forward voltage drop of 2 V. A common-emitter current gain of 40 was measured on these devices. A specific on-resistance of 6.0 mW-cm2 was observed at room temperature. The onresistance increases at higher temperatures, while the current gain decreases to 30 at 275°C. In addition, an integrated Darlington pair with an active area of 3 mm x 3 mm showed a collector current of 30 A at a forward drop of 4 V at room temperature. A current gain of 2400 was measured on these devices. A BVCEO of 1000 V was measured on both of these devices.

10 kV, 10 A Bipolar Junction Transistors and Darlington Transistors on 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 1025-1028 ◽  
Author(s):  
Qing Chun Jon Zhang ◽  
Robert Callanan ◽  
Anant K. Agarwal ◽  
Albert A. Burk ◽  
Michael J. O'Loughlin ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Voltage Drop ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Collector Current ◽  
Forward Voltage ◽  
Collector Voltage ◽  
Forward Voltage Drop ◽  
Chip Size ◽  
Dc Current

4H-SiC Bipolar Junction Transistors (BJTs) and hybrid Darlington Transistors with 10 kV/10 A capability have been demonstrated for the first time. The SiC BJT (chip size: 0.75 cm2 with an active area of 0.336 cm2) conducts a collector current of 10 A (~ 30 A/cm2) with a forward voltage drop of 4.0 V (forced current gain βforced: 20) corresponding to a specific on-resistance of ~ 130 mΩ•cm2 at 25°C. The DC current gain, β, at a collector voltage of 15 V is measured to be 28 at a base current of 1 A. Both open emitter breakdown voltage (BVCBO) and open base breakdown voltage (BVCEO) of ~10 kV have been achieved. The 10 kV SiC Darlington transistor pair consists of a 10 A SiC BJT as the output device and a 1 A SiC BJT as the driver. The forward voltage drop of 4.5 V is measured at 10 A of collector current. The DC forced current gain at the collector voltage of 5.0 V was measured to be 440 at room temperature.

High Voltage 4H-SiC BJTs with Deep Mesa Edge Termination

2011 ◽  
Vol 679-680 ◽  
pp. 710-713
Author(s):  
Jian Hui Zhang ◽  
Jian Hui Zhao ◽  
Xiao Hui Wang ◽  
Xue Qing Li ◽  
Leonid Fursin ◽  
...  
Keyword(s):  
High Voltage ◽  
Active Area ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Edge Termination ◽  
Direct Edge ◽  
Dc Current

This paper reports our recent study on 4H-SiC power bipolar junction transistors (BJTs) with deep mesa edge termination. 1200 V – 10 A 4H-SiC power BJTs with an active area of 4.64 mm2 have been demonstrated using deep mesa for direct edge termination and device isolation. The BJT’s DC current gain () is about 37, and the specific on-resistance (RSP-ON) is ~ 3.0 m-cm2. The BJT fabrication is substantially simplified and an overall 10% reduction in the device area is achieved compared to the multi-step JTE-based SiC-BJTs.

1836 V, 4.7 mΩ•cm2 High Power 4H-SiC Bipolar Junction Transistor

2006 ◽  
Vol 527-529 ◽  
pp. 1417-1420 ◽  
Author(s):  
Jian Hui Zhang ◽  
Jian Wu ◽  
Petre Alexandrov ◽  
Terry Burke ◽  
Kuang Sheng ◽  
...  
Keyword(s):  
High Power ◽  
Active Area ◽  
Current Gain ◽  
High Current ◽  
Theoretical Limit ◽  
Collector Current ◽  
Bipolar Junction Transistor ◽  
Blocking Voltage ◽  
Saturation Region ◽  
Junction Transistor

This paper reports recent progress in the development of high power 4H-SiC BJTs based on an improved device design and fabrication scheme. Near theoretical limit high blocking voltage of VCEO=1,836 V has been achieved for 4H-SiC BJTs based on a drift layer of only 12 μm, doped to 6.7x1015 cm-3. The collector current measured for a single cell BJT with an active area of 0.61 mm2 is up to IC=9.87 A (JC=1618 A/cm2). The collector current is 7.64 A (JC=1252 A/cm2) at VCE=5.9 V in the saturation region, corresponding to an absolute specific on-resistance (RSP_ON) of 4.7 m9·cm2. From VCE=2.4 V to VCE= 5.8 V, the BJT has a differential RSP_ON of only 3.9 m9·cm2. The current gain is about 8.8 at Ic=5.3 A (869 A/cm2). This 4H-SiC BJT shows a V2/RSP_ON of 717 MW/cm2, which is the highest value reported to date for high-voltage and high-current 4H-SiC BJTs. A verylarge area 4H-SiC BJT with an active area of 11.3 mm2 is also demonstrated.

Effect of Base Impurity Concentration on DC Characteristics of Double Ion Implanted 4H-SiC BJTs

2008 ◽  
Vol 1069 ◽  
Author(s):  
Taku Tajima ◽  
Satoshi Uchiumi ◽  
Kenta Tsukamoto ◽  
Kazumasa Takenaka ◽  
Masataka Satoh ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Impurity Concentration ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Injection Level ◽  
Collector Current ◽  
Base Resistance ◽  
Dc Characteristics ◽  
High Base ◽  
Ion Implanted

ABSTRACTDouble ion implanted 4H-SiC bipolar junction transistors (BJTs) are fabricated by Al and N ion implantation to the base and emitter. The current gain of 3 is obtained at the base Al concentration of 1 × ∼ 1017 /cm3. The collector current as a function of the base Gummel number suggests that double ion implanted 4H-SiC BJT operates in the intrinsic region below the emitter in the low injection level. The high base resistance restricts the base current at VBE as low as 3 V.

scholarly journals Electrical characterization of commercial NPN bipolar junction transistors under neutron and gamma irradiation

2014 ◽  
Vol 29 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Myo OO ◽  
Nahrul Rashid ◽  
Julia Karim ◽  
Zin Mohamed ◽  
Rosminazuin Rahim ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Electrical Characterization ◽  
Neutron Radiation ◽  
Space Mission ◽  
Depletion Region ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Collector Current ◽  
Recombination Current ◽  
Gamma Radiations

Electronics components such as bipolar junction transistors, diodes, etc. which are used in deep space mission are required to be tolerant to extensive exposure to energetic neutrons and ionizing radiation. This paper examines neutron radiation with pneumatic transfer system of TRIGA Mark-II reactor at the Malaysian Nuclear Agency. The effects of the gamma radiation from Co-60 on silicon NPN bipolar junction transistors is also be examined. Analyses on irradiated transistors were performed in terms of the electrical characteristics such as current gain, collector current and base current. Experimental results showed that the current gain on the devices degraded significantly after neutron and gamma radiations. Neutron radiation can cause displacement damage in the bulk layer of the transistor structure and gamma radiation can induce ionizing damage in the oxide layer of emitter-base depletion layer. The current gain degradation is believed to be governed by the increasing recombination current in the base-emitter depletion region.

scholarly journals Total Dose Effects on 4H-SiC Bipolar Junction Transistors

2017 ◽  
Vol 897 ◽  
pp. 579-582
Author(s):  
Sethu Saveda Suvanam ◽  
Luigia Lanni ◽  
Bengt Gunnar Malm ◽  
Carl Mikael Zetterling ◽  
Anders Hallén
Keyword(s):  
Total Dose ◽  
Detailed Analysis ◽  
Surface Recombination ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Displacement Damage ◽  
Base Current ◽  
Dose Effects ◽  
Order Of Magnitude ◽  
Total Dose Effects

In this work, total dose effects on 4H-SiC bipolar junction transistors (BJT) are investigated. Three 4H-SiC NPN BJT chips are irradiated with 3MeV protons with a dose of 1×1011, 1×1012 and 1×1013 cm-2, respectively. From the measured reciprocal current gain it is observed that 4H-SiC NPN BJT exposed to protons suffer both displacement damage and ionization, whereas, a traditional Si BJT suffers mainly from displacement damage. Furthermore, bulk damage introduction rates for SiC BJT were extracted to be 3.3×10-15 cm2, which is an order of magnitude lower compared to reported Si values. Finally, from detailed analysis of the base current at low injection levels, it is possible to distinguish when surface recombination leakage is dominant over bulk recombination.

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.

Fabrication and Characterization of Hydrogenated Amorphous Silicon Bipolar Thin Film Transistor (B-TFT)

2004 ◽  
Vol 808 ◽  
Author(s):  
Yue Kuo ◽  
Yu Lei ◽  
Helinda Nominanda
Keyword(s):  
Thin Film ◽  
Thin Film Transistor ◽  
Chemical Vapor ◽  
Base Layer ◽  
Current Gain ◽  
Collector Current ◽  
Literature Report ◽  
Small Current ◽  
Operation Speed ◽  
Driving Capability

ABSTRACTThe conventional a-Si:H thin film transistor (TFT) is a field effect transistor (FET), which has disadvantages of a low operation speed and a small current driving capability. To achieve a higher speed and larger current driving capability, a potential solution is to fabricate the a-Si:H-based bipolar thin film transistor (B-TFT). In this study, a-Si:H p-i-n junctions were prepared and studied in order to determine the proper layer thickness for good junction behaviors. B-TFTs composed of a stacked structure of n+/i/p/i/n+ were then fabricated. The complete B-TFT was made using plasma enhanced chemical vapor deposition (PECVD) to deposit all doped and undoped a-Si:H layers and SiNx dielectrics at 250°C. Reactive ion etching (RIE) and wet etching methods were used to define base and emitter regions and contacts. The I-V characteristics of the complete B-TFT were investigated. The common-emitter current gain is 3∼6, which is larger than the literature report of 2∼3. In addition, a collector current larger than the literature value was obtained. A significant current noise was observed, which may be contributed to the high series resistance of the base layer and defective junction interfaces. In this paper, process and structure influences on the a-Si:H junction and B-TFT performances are discussed.

The Influence of Dopant Type on Polysilicon Grain Growth and Solid Phase Epitaxial Regrowth

1997 ◽  
Vol 3 (S2) ◽  
pp. 477-478
Author(s):  
M.G. Shlepr ◽  
G.A. Schrantz ◽  
A.L. Rivoli ◽  
G. Bajor
Keyword(s):  
Grain Growth ◽  
Solid Phase ◽  
Convergent Beam Electron Diffraction ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Process Technology ◽  
Epitaxial Regrowth ◽  
Transmission Electron ◽  
Polysilicon Emitters ◽  
Convergent Beam

A recent process technology to manufacture bipolar junction transistors utilizes polysilicon emitters. Polysilicon is deposited, appropriately doped to form both NPN and PNP transistors, and exposed to temperatures that result in grain growth. Since polysilicon is in contact with Si( 100) at the emitter, base, and collector (Fig. 1), solid phase epitaxial regrowth might also occur. Production runs with this structure occasionally produce transistors with low current gain. High and low gain NPN and PNP transistors were characterized by transmission electron microscopy.Vertical sections through NPN/PNP transistor arrays were made by the wedge technique, low-angle ion milled to electron-transparency, and viewed at 200 KV. The grain size of the polysilicon on oxide was recorded and estimated. The extent of epitaxial regrowth was quantified for each of the Si (100) contact areas. Convergent Beam Electron Diffraction (CBED) was used to confirm the orientation of the presumed regrown polysilicon.

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