Developments of SiC DioMOS (Diode Integrated SiC MOSFET)

2014 ◽  
Vol 1693 ◽  
Author(s):  
Makoto Kitabatake

ABSTRACTSiC power devices can handle large power and high frequency switching beyond the Si power devices. Typical full-SiC power modules are composed of both SiC-MOSFETs and SiC-SBDs to suppress the degradation of Ron of SiC-MOSFET during the bipolar reverse-current flow while there will be unfavorable consequences such as increased material cost, larger area, and larger wiring inductances. Panasonic has proposed the SiC-DioMOS which successfully integrates the unipolar reverse diode without any increase of chip size from the original DIMOS transistor. The SiC-DioMOS utilizes the highly-doped n-type epitaxial channel under the MOS gate for the FET channel and also for the reverse conduction path of the diode. Thickness and concentration of the highly-doped n-typed channel are carefully designed to achieve reasonable Vth of the MOSFET and Vf0 barrier constituting the diode current. The MOSFET and also the MOS-channel diode completely operate under unipolar mode. The SiC-DioMOS with BVds=1700V, Ron=20mΩ、Vth=4.5V, Vf0=0.8V is successively fabricated using the state-of-the-art epitaxial-growth technique. Fast switching of tr=58ns and tf=13ns is confirmed. The SiC-DioMOS meets practical standards for safety operation of high-power fast switching without SiC-SBD.

2018 ◽  
Vol 180 ◽  
pp. 04002
Author(s):  
Marek Adamowicz ◽  
Zbigniew Krzemiński ◽  
Paweł Stec

Semiconductor power devices made from silicon carbide (SiC) reached a level of technology enabling their widespread use in power converters. Two different approaches to implementation of modern traction converters in electric multiple units (EMU) have been presented in recent years: (i) 3.3-kV SiC MOSFET-based three-level PWM inverter with regenerative braking and (ii) 6.5-kV IGBT-based fourquadrant power electronic traction transformer (PETT). The former has successfully reached optimized dimensions and efficiency but still requires a bulky line frequency transformer for multisystem applications. The latter characterizes inherent galvanic isolation from AC traction, which is realized by cascaded system of power electronic cells containing medium frequency transformers (MFT). The downsizing of the 6.5-kV IGBT-based cells is, however, problematic. The present paper proposes a different approach, that involves the use of a fast switching 1.2-kV SiC MOSFETS. The SiC-based PETT proposed in the paper is dedicated first for the DC traction. For multi-system application the input voltage of the proposed PETT can be adjusted using weight-optimized adjusting autotransformer. Thanks to utilization of fast-switching SiCbased power modules the weight and size of the power electronic cells can be optimized in a convenient way.


2014 ◽  
Vol 778-780 ◽  
pp. 911-914 ◽  
Author(s):  
Atsushi Ohoka ◽  
Nobuyuki Horikawa ◽  
Tsutomu Kiyosawa ◽  
Haruyuki Sorada ◽  
Masao Uchida ◽  
...  

Device technologies of SiC MOSFETs have nearly matured to the level of mass production and one of the remaining tasks is to serve better solutions in view of both costs and performances for practical systems. Elimination of external reverse diodes in inverter circuits is one of the solutions, by which total area of the SiC chips is greatly reduced leading to lower material cost. A DioMOS (Diode in SiC MOSFET) successfully integrates the reverse diode without any increase of the chip size from the original MOS transistor by utilizing an n-type epitaxial channel under the MOS gate for the reverse conduction path of the diode. The basic concept of the DioMOS has been proposed [1]; meanwhile, further reduction of the on-state resistance together with confirmation of high-speed switching is necessary for its application in power switching systems. In this paper, low on-state resistance (Ron) of 40mΩ and blocking voltage (BVds) of 1700V as well as improved switching performances of DioMOS are demonstrated. The measured results suggest DioMOS to be satisfactory for practical use.


2017 ◽  
Vol 897 ◽  
pp. 689-692
Author(s):  
Stefan Matlok ◽  
Tobias Erlbacher ◽  
Florian Krach ◽  
Bernd Eckardt

Large power modules include several parallel mounted chips per switch to raise active area and current. By the electro-mechanical connection interface, the resulting large parasitic inductance is a huge problem especially for very fast switching SiC devices. This challenge is handled by many approaches, but these recent developments require additional development effort along all aspects of the power module, e.g. smart DBC layout, low inductive top side metallization, special terminal designs or additional pins. In this paper we demonstrate an approach to enable excellent switching performance with con-ventional power module technologies: By using a recently developed monolithic silicon RC (Si-RC) element to decouple the bus bar, this problem can be solved in a very efficient way. The Si-RC element is assembled directly adjacent to the power switches on the DBC. This allows a significant reduction of the SiC chip area by minimizing the power losses caused by the switching transients from the parasitic DC-link and module inductances.


2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000065-000072 ◽  
Author(s):  
Sayan Seal ◽  
Michael D. Glover ◽  
H. Alan Mantooth

Abstract This paper presents the plan and initial feasibility studies for an Integrated Wire Bondless Power Module (IWPM). Contemporary power modules are moving toward unprecedented levels of power density. The ball has been set rolling by a drastic reduction in the size of bare die power devices themselves owing to the advent of wide band gap semiconductors like silicon carbide (SiC) and gallium nitride (GaN). SiC has capabilities of operating at much higher temperatures and faster switching speeds as compared with its silicon counterparts, while being a fraction of their size. However, electronic packaging technology has not kept pace with these developments. High performance packaging technologies do exist in isolation, but there has been limited success in integrating these disparate efforts into a single high performance package of sufficient reliability. This paper lays the foundation for an electronic package which is designed to completely leverage the benefits of SiC semiconductor technology, with a focus on high reliability and fast switching capability.


2016 ◽  
Vol 13 (4) ◽  
pp. 169-175
Author(s):  
Sayan Seal ◽  
Michael D. Glover ◽  
H. Alan Mantooth

This article presents the plan and initial feasibility studies for an Integrated Wire Bond-less Power Module. Contemporary power modules are moving toward unprecedented levels of power density. The ball has been set rolling by a drastic reduction in the size of bare die power devices owing to the advent of wide bandgap semiconductors such as silicon carbide (SiC) and gallium nitride. SiC has capabilities of operating at much higher temperatures and faster switching speeds compared with its silicon counterparts, while being a fraction of their size. However, electronic packaging technology has not kept pace with these developments. High-performance packaging technologies do exist in isolation, but there has been limited success in integrating these disparate efforts into a single high-performance package of sufficient reliability. This article lays the foundation for an electronic package designed to completely leverage the benefits of SiC semiconductor technology, with a focus on high reliability and fast switching capability. The interconnections between the gate drive circuitry and the power devices were implemented using a low temperature cofired ceramic interposer.


2011 ◽  
Vol 324 ◽  
pp. 437-440
Author(s):  
Raed Amro

There is a demand for higher junction temperatures in power devices, but the existing packaging technology is limiting the power cycling capability if the junction temperature is increased. Limiting factors are solder interconnections and bond wires. With Replacing the chip-substrate soldering by low temperature joining technique, the power cycling capability of power modules can be increased widely. Replacing also the bond wires and using a double-sided low temperature joining technique, a further significant increase in the life-time of power devices is achieved.


2013 ◽  
Vol 740-742 ◽  
pp. 881-886 ◽  
Author(s):  
Hiroyuki Okino ◽  
Norifumi Kameshiro ◽  
Kumiko Konishi ◽  
Naomi Inada ◽  
Kazuhiro Mochizuki ◽  
...  

The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.


2018 ◽  
Vol 2018 (1) ◽  
pp. 000317-000325
Author(s):  
Sayan Seal ◽  
Brandon Passmore ◽  
Brice McPherson

Abstract The performance of SiC power devices has demonstrated superior characteristics as compared to conventional Silicon (Si) devices. Some of the advantages of SiC power devices over Si include higher voltage blocking capability, low specific on-resistance, high switching frequency, high temperature operation, and high power density. Thus, SiC modules are capable of processing significant levels of power within much smaller volumes compared with its Si counterparts. These high thermal loads present a formidable challenge in integrating SiC devices in power modules. For example, known-good materials and processes for silicon power modules are not rated at the aggressive operating conditions associated with SiC devices. Two of the most critical interfaces in a power electronics module are the die-attach and substrate- attach. A degradation in these interfaces often results in potentially catastrophic electrical and thermal failure. Therefore, it is very important to thoroughly evaluate die-attach materials before implementing them in SiC power modules. This paper presents the methodology for the evaluation of die attach materials for SiC power modules. Preforms of a lead-free high-temperature attach material were used to perform a die and substrate attach process on a conventional power module platform. The initial attach quality was inspected using non- destructive methods consisting of acoustic microscopy and x-ray scanning. Die attach and substrate attach voiding of < 5% was obtained indicating a very good attach quality. Cross-sectioning techniques were used to validate the inspection methods. The initial attach strength was measured using pull tests and shear tests. The measurements were repeated at the rated temperature of the module to ensure that the properties did not degrade excessively at the service temperature. At the rated module temperature of 175 °C, the die bonding strength was found to be ~ 75 kg. This was only 25% lower than the strength at room temperature. In addition, the contact pull strength was measured to be > 90 kg at 175 °C, which was 25% lower than the value measured at room temperature. The effect of power cycling and thermal cycling on the quality and strength of the die and substrate attach layers was also investigated.


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