Lifetime Enhancement of 4H-SiC PiN Diodes Using High Temperature Oxidation Treatment

2018 ◽  
Vol 924 ◽  
pp. 440-443
Author(s):  
Yeganeh Bonyadi ◽  
Peter M. Gammon ◽  
Olayiwola Alatise ◽  
Roozbeh Bonyadi ◽  
Philip A. Mawby
Keyword(s):  
High Temperature ◽  
Thermal Oxidation ◽  
Carrier Lifetime ◽  
Drift Region ◽  
Electrical Characteristics ◽  
Pin Diodes ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
Bipolar Devices ◽  
Minority Carriers

In this paper, the application of a high temperature thermal oxidation and annealing process to 4H-SiC PiN diodes with 35 μm thick drift regions is explored, the aim of which was to increase the carrier lifetime in the 4H-SiC. Diodes were fabricated using 4H-SiC material and underwent a thermal oxidation in dry pure O2 at 1550◦C followed by an argon anneal at the same temperature. Reverse recovery tests indicated a carrier lifetime increase of around 42% which is due to increase of excessive minority carriers in the drift region. The switching results illustrate that the use of this process is a highly effective and efficient way of enhancing the electrical characteristics of high voltage 4H-SiC bipolar devices.

Enhanced Forward Bias Operation of 4H-SiC PiN Diodes Using High Temperature Oxidation

2014 ◽  
Vol 1693 ◽  
Author(s):  
Craig A. Fisher ◽  
Michael R. Jennings ◽  
Yogesh K. Sharma ◽  
Dean P. Hamilton ◽  
Stephen M. Thomas ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Oxidation ◽  
Carrier Lifetime ◽  
Voltage Drop ◽  
Forward Bias ◽  
Control Sample ◽  
Pin Diodes ◽  
Temperature Oxidation ◽  
Current Voltage ◽  
Forward Voltage Drop

ABSTRACTIn this paper, high temperature (>1400°C) thermal oxidation has been applied, for the first time, to 4H-SiC PiN diodes with thick (110 μm) drift regions, for the purpose of increasing the carrier lifetime in the semiconductor. PiN diodes were fabricated using 4H-SiC material that had undergone thermal oxidation performed at 1400°C, 1500°C and 1600°C, then were electrically characterized. Forward current-voltage (I-V) measurements showed that thermally oxidized PiN diodes exhibited considerably improved electrical characteristics, with devices oxidized at 1500°C having a forward voltage drop (VF) of 4.15 V and a differential on-resistance (Ron,diff) of 8.9 mΩ-cm2 at 100 A/cm2 and 25°C. Compared to typical control sample PiN diode characteristics, this equated to an improvement of 8% and 23% for VF and Ron,diff, respectively. From analysis of the reverse recovery characteristics, the carrier lifetime of the PiN diodes oxidized at 1500°C was found to be 1.05 μs, which was an improvement of around 30% compared to the control sample PiN diodes.

Improvement of Minority Carrier Lifetime in Thick 4H-SiC Epi-layers by Multiple Thermal Oxidations and Anneals

2013 ◽  
Vol 1538 ◽  
pp. 329-333 ◽  
Author(s):  
Lin Cheng ◽  
Michael J. O’Loughlin ◽  
Alexander V. Suvorov ◽  
Edward R. Van Brunt ◽  
Albert A. Burk ◽  
...  
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Power Devices ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
Oxidation Step ◽  
High Temperature Anneal ◽  
Lifetime Enhancement

ABSTRACTThis paper details the development of a technique to improve the minority carrier lifetime of 4H-SiC thick (≥ 100 μm) n-type epitaxial layers through multiple thermal oxidations. A steady improvement in lifetime is seen with each oxidation step, improving from a starting ambipolar carrier lifetime of 1.09 µs to 11.2 µs after 4 oxidation steps and a high-temperature anneal. This multiple-oxidation lifetime enhancement technique is compared to a single high-temperature oxidation step, and a carbon implantation followed by a high-temperature anneal, which are traditional ways to achieve high ambipolar lifetime in 4H-SiC n-type epilayers. The multiple oxidation treatment resulted in a high minimum carrier lifetime of 6 µs, compared to < 2 µs for other treatments. The implications of lifetime enhancement to high-voltage/high-current 4H-SiC power devices are also discussed.

In situ Raman spectroscopy study on the effect of antioxidants on high temperature oxidation properties of TMPTO

2019 ◽  
Vol 71 (5) ◽  
pp. 706-711 ◽  
Author(s):  
Bingxue Cheng ◽  
Haitao Duan ◽  
Yongliang Jin ◽  
Lei Wei ◽  
Jia Dan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Thermal Oxidation ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
In Situ Raman Spectroscopy ◽  
Temperature Oxidation ◽  
Content Type ◽  
Structure Changes ◽  
Oxidation Properties

Purpose This paper aims to investigate the thermal oxidation characteristics of the unsaturated bonds (C=C) of trimethylolpropane trioleate (TMPTO) and to reveal the high temperature oxidation decay mechanism of unsaturated esters and the nature of the anti-oxidation properties of the additives. Design/methodology/approach Using a DXR laser microscopic Raman spectrometer and Linkam FTIR600 temperature control platform, the isothermal oxidation experiments of TMPTO with or without 1.0 wt. % of different antioxidants were performed. Findings The results indicated that the Raman peaks of =C-H, C=C and -CH2- weaken gradually with prolonged oxidation time, and the corresponding Raman intensities drop rapidly at higher temperatures. The aromatic amine antioxidant can decrease the attenuation of peak intensity, as it significantly reduces the rate constant of C=C thermal oxidation. The hindered phenolic antioxidant has a protective effect during the early stages of oxidation (induction period), but it may accelerate the oxidation of C=C afterwards. Originality/value Research on the structure changes of synthetic esters during oxidation by Raman spectroscopy will be of great importance in promoting the use of Raman spectroscopy to analyze the oxidation of lubricants.

Impact of Carrier Lifetime Enhancement Using High Temperature Oxidation on 15 kV 4H-SiC P-GTO Thyristor

2017 ◽  
Vol 897 ◽  
pp. 587-590 ◽  
Author(s):  
Sei Hyung Ryu ◽  
Daniel J. Lichtenwalner ◽  
Edward van Brunt ◽  
Craig Capell ◽  
Michael J. O’Loughlin ◽  
...  
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Voltage Drop ◽  
Current Gain ◽  
Slight Reduction ◽  
Temperature Oxidation ◽  
Forward Voltage Drop ◽  
P Type ◽  
The Impact ◽  
Lifetime Enhancement

The impact of the lifetime enhancement process using high temperature thermal oxidation method on 4H-SiC P-GTOs was investigated. 15 kV 4H-SiC P-GTOs with 140 μm thick drift layers, with and without 1450°C lifetime enhancement oxidation (LEO) process, were compared. The LEO process increased the average carrier lifetime in p-type epi layer from 0.9 μs to 6.25 μs, and it was observed that the effectiveness of the lifetime enhancement process was very sensitive to the doping concentration. The device with the LEO process showed a significant reduction in forward voltage drop and a substantially lower holding current, as expected from the carrier lifetime measurements. However, a slight reduction in blocking capability was also observed from the devices treated with LEO process. The common emitter current gain (β) of the wide base test NPN BJT was approximately 10X higher for the wafer with LEO process.

A Case for High Temperature, High Voltage SiC Bipolar Devices

2007 ◽  
Vol 556-557 ◽  
pp. 687-692 ◽  
Author(s):  
Anant K. Agarwal
Keyword(s):  
High Temperature ◽  
High Voltage ◽  
Low Voltage ◽  
Schottky Diodes ◽  
Life Time ◽  
Extreme Environment ◽  
Junction Temperature ◽  
Current Gain ◽  
Pin Diodes ◽  
Bipolar Devices

The last three years have seen a rapid growth of 600 V and 1200 V SiC Schottky diodes primarily in the Power Factor Correction (PFC) circuits. The next logical step is introduction of a SiC MOSFET to not only further improve the power density and efficiency of the PFC circuits but also to enable the entry of all SiC power modules in Pulse Width Modulated (PWM) based power converters such as motor control in 600-1200 V range. The combination of SiC MOSFET and Schottky diodes will offer 60-80% lower losses in most low voltage applications at normal operating temperatures (< 200°C) where no significant improvements in packaging are required. This will cover most commercial applications with the exception of those having to function under extreme environment (>200°C) such as applications in automotive, aerospace and oil/gas exploration. For these high temperature applications, a case can be made for 600 - 2000 V Bipolar Junction Transistors (BJTs) and PiN diodes provided we do our homework on high temperature packaging. A number of interesting device related problems persist in bipolar devices such as forward voltage increase in PiN diodes and current gain degradation in BJTs. For very high voltage (>10 kV) applications such as those found in utilities (Transmission and Distribution), Large Drives and Traction, a case can be made for >10 kV PiN diodes, IGBTs, Thyristors and GTOs. While IGBTs will be restricted to <200°C junction temperature, the PiN diodes, Thyristors and GTOs may be operated at >250°C junction temperature provided that the high temperature, high voltage packaging issues are also addressed. Significant progress has been made in the development of the p-channel IGBTs and GTOs. The main issues seem to be the VF degradation due to stacking fault formation and improvement of minority carrier life-time.

Electrical Characteristics of 4H-SiC Pin Diode with Carbon Implantation or Thermal Oxidation

2012 ◽  
Vol 717-720 ◽  
pp. 989-992 ◽  
Author(s):  
Koji Nakayama ◽  
Atsushi Tanaka ◽  
Katsunori Asano ◽  
Tetsuya Miyazawa ◽  
Masahiko Ito ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Room Temperature ◽  
Surface Recombination ◽  
Electrical Characteristics ◽  
Bulk Carrier ◽  
Standard Process ◽  
Pin Diodes ◽  
Voltage Drops ◽  
Implantation Process ◽  
Reverse Recovery Time

The forward voltage drops of pin diodes with the carbon implantation process or thermal oxidation process using a drift layer of 120 μm thick are around 4.0 V and are lower than those with the standard process. The reverse recovery characteristics of diodes with the standard process or carbon implantation at room temperature show almost the same tendency. In the reverse recovery characteristics at 250 oC, pin diodes with carbon implantation process, however, have the longer reverse recovery time than those with the standard process. These characteristics indicate that a recombination path other than the bulk carrier lifetime, such as the interfaces or the surface recombination, becomes dominant in the reverse recovery characteristics at room temperature.

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