5.8-kV Implantation-Free 4H-SiC BJT With Multiple-Shallow-Trench Junction Termination Extension
Summary (1 min read)
I. INTRODUCTION
- ILICON carbide bipolar junction transistors (BJTs) in the 3-7-kV range with low on-resistance (R ON ) are very attractive devices for industrial applications due to their low loss and fast switching speed.
- Among them, implantation-free devices with low R ON have the advantage of preventing life-time-killing defects and current degradation caused by ion implantation [10] .
- These devices are based on etched junction termination extensions (JTEs) in which the remaining dose of the JTEs is controlled by the etching depth.
II. DEVICE STRUCTURE AND FABRICATION
- Trench structures gradually decreasing in dimensions have been formed on the first JTE (see Fig. 1(c) ).
- Depending on the design, the depth of the trenches can be controlled by the etching of the other layers with no additional mask.
- Then, inductively coupled plasma (ICP) deep etching is used to form the emitter and mesa.
- To improve the current spreading through the contacts, 500 nm of Al was deposited and formed on the n-and p-contacts.
III. RESULTS AND DISCUSSION
- The current flow in the thick collector layer is analyzed by 2-D simulation and the estimated equivalent active area of the device is 0.065 mm 2 .
- The maximum breakdown voltage variation (ΔBV) of 700 V and1700 V is measured for the ST-JTE and conventional double-JTE for 20% variation in the remaining dose of the p-layer, respectively.
- The influence of charges at the oxide/SiC interface on the breakdown voltage of SiC devices has been reported [15] .
- Also, it is apparent that higher number of trenches with smaller widths results in better electric field distribution.
- Considering the lithography limit to 1 µm, the optimized result is obtained for the ST-JTE with seven trenches.
IV. CONCLUSION
- An implantation-free 4H-SiC BJT with multiple-shallow-trench JTE structure (ST-JTE) is presented.
- No extra mask is required to form these trenches which result in a simpler process without any further misalignment issue.
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Cites methods from "5.8-kV Implantation-Free 4H-SiC BJT..."
...years, several methods to realize multiple-zone JTE have been reported [15], [16]....
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18 citations
Cites background from "5.8-kV Implantation-Free 4H-SiC BJT..."
...In recent years, there has been increasing interest to improve the termination efficiency and approach to the ideal breakdown voltage (BV) [3-13]....
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13 citations
References
394 citations
"5.8-kV Implantation-Free 4H-SiC BJT..." refers background in this paper
...85 kV is obtained which corresponds to 93% of the theoretical value [13]....
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218 citations
"5.8-kV Implantation-Free 4H-SiC BJT..." refers methods in this paper
...85 was deposited and patterned on the base layer followed by annealing in N2 at 815 °C for 2 min to form the p-contacts [14]....
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101 citations
73 citations
"5.8-kV Implantation-Free 4H-SiC BJT..." refers background in this paper
...The influence of charges at the oxide/SiC interface on the breakdown voltage of SiC devices has been reported [15]....
[...]