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.

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.

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.

High Temperature Characterization of 4H-SiC Bipolar Junction Transistors

2006 ◽  
Vol 527-529 ◽  
pp. 1437-1440 ◽  
Author(s):  
Sumi Krishnaswami ◽  
Anant K. Agarwal ◽  
Jim Richmond ◽  
Craig Capell ◽  
Sei Hyung Ryu ◽  
...  
Keyword(s):  
High Temperature ◽  
Leakage Current ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Linear Region ◽  
Collector Voltage ◽  
Avalanche Behavior ◽  
Dc Current ◽  
Recent Demonstration

This paper summarizes the recent demonstration of 3200 V, 10 A BJT devices with a high common emitter current gain of 44 in the linear region, and a specific on-resistance of 8.1 mΩ- cm2 (10 A at 0.90 V with a base current of 350 mA and an active area of 0.09 cm2). The onresistance increases to 40 mΩ-cm2 at 350°C, while the DC current gain decreases to 30. A sharp avalanche behavior was observed with a leakage current of 10 μA at a collector voltage of 3.2 kV.

Forward Active and Blocking Performance of 4H-SiC Bipolar Junction Transistors

2005 ◽  
Vol 888 ◽  
Author(s):  
Santhosh Balachandran ◽  
T. Paul Chow ◽  
Anant Agarwal
Keyword(s):  
High Voltage ◽  
Minority Carrier ◽  
Surface Recombination ◽  
Current Gain ◽  
Surface Recombination Velocity ◽  
Bipolar Junction Transistors ◽  
Carrier Lifetimes ◽  
Minority Carrier Lifetimes ◽  
Recombination Velocity ◽  
The Impact

ABSTRACTWe evaluate the performance capabilities and limitations of high voltage 4H-SiC based Bipolar Junction Transistors (BJTs). Experimental forward characteristics of a 4kV BJT are studied and simulations are employed to determine the factors behind the higher than expected specific on-resistance (Ron,sp) for the device. The impact of material (minority carrier lifetimes), processing (surface recombination velocity) and design (p contact spacing from the emitter mesa) parameters on the forward active performance of this device are discussed and ways to lower Ron,sp, below the unipolar level, and increase the gain (β) are examined. A correlation between the open base blocking behavior (forward blocking) and the current gain (forward active) for 4H-SiC based high-voltage BJTs with lightly doped collector regions is presented and experimental device characteristics are utilized to verify our numerical analysis.

Modification of Etched Junction Termination Extension for the High Voltage 4H-SiC Power Devices

2016 ◽  
Vol 858 ◽  
pp. 978-981 ◽  
Author(s):  
Hossein Elahipanah ◽  
Arash Salemi ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Current Density ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Power Devices ◽  
Process Step ◽  
Single Finger ◽  
Maximum Current

High voltage 4H-SiC bipolar junction transistors (BJTs) with modified etched junction termination extension (JTE) were fabricated and optimized in terms of the length (LJTE) and remaining dose (DJTE) of JTEs. It is found that for a given total termination length (Σ LJTEi), a decremental JTE length from the innermost edge to the outermost mesa edge of the device will result in better modification of the electric field. A breakdown voltage (BV) of 4.95 kV is measured for the modified device which shows ~20% improvement of the termination efficiency for no extra cost or extra process step. Equal-size BJTs by interdigitated-emitter with different number of fingers and cell pitches were fabricated. The maximum current gain of 40 is achieved for a single finger device with the emitter width of 40 µm at IC = 0.25 A (JC = 310 A/cm2) which corresponds to RON = 33 mΩ.cm2. It is presented that the current gain decreases by having more fingers while the maximum current gain is achieved at higher current density.

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.

4H-SiC Bipolar Junction Transistors with Graded Base Doping Profile

2009 ◽  
Vol 615-617 ◽  
pp. 829-832 ◽  
Author(s):  
Jian Hui Zhang ◽  
Leonid Fursin ◽  
Xue Qing Li ◽  
Xiao Hui Wang ◽  
Jian Hui Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Vapor ◽  
Doping Profile ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Bipolar Junction Transistor ◽  
Blocking Voltage ◽  
Junction Transistor ◽  
Dc Current ◽  
Base Doping

This work reports 4H-SiC bipolar junction transistor (BJT) results based upon our first intentionally graded base BJT wafer with both base and emitter epi-layers continuously grown in the same reactor. The 4H-SiC BJTs were designed to improve the common emitter current gain through the built-in electrical fields originating from the grading of the base doping. Continuously-grown epi-layers are also believed to be the key to increasing carrier lifetime and high current gains. The 4H-SiC BJT wafer was grown in an Aixtron/Epigress VP508, a horizontal hot-wall chemical vapor deposition reactor using standard silane/propane chemistry and nitrogen and aluminum dopants. High performance 4H-SiC BJTs based on this initial non-optimized graded base doping have been demonstrated, including a 4H-SiC BJT with a DC current gain of ~33, specific on-resistance of 2.9 mcm2, and blocking voltage VCEO of over 1000 V.

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.

Edge Termination With Enhanced Field-Limiting Rings Insensitive to Surface Charge for High-Voltage SiC Power Devices

2020 ◽  
Vol 67 (7) ◽  
pp. 2850-2853
Author(s):  
Takashi Hirao ◽  
Hidekatsu Onose ◽  
Kan Yasui ◽  
Mutsuhiro Mori
Keyword(s):  
Surface Charge ◽  
High Voltage ◽  
Power Devices ◽  
Edge Termination

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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