Single Material Ohmic Contacts Simultaneously Formed on the Source/P-Well/Gate of 4H-SiC Vertical MOSFETs

Kiritani, Norihiko; Hoshi, Masakatsu; Tanimoto, Satoshi; Adachi, Kazuhiro; Nishizawa, Shin Ichi; Yatsuo, Tsutomu; Okushi, Hideyo; Arai, Kazuo

doi:10.4028/www.scientific.net/msf.433-436.669

Cited by 17 publications

(10 citation statements)

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“…Fursin et al [3] reported that a nickel contact, which was known as a typical ohmic contact material for n-type SiC [6], showed ohmic behavior after annealing at 1050 °C for both n-and p-type SiC implanted with nitrogen and aluminum at the levels of the order of 10 19 and 10 21 cm -3 , respectively. Tanimoto et al [4] and Kiritani et al [5] also reported simultaneous formation for Ni-based contacts such as Ni and Al/Ni to SiC heavily doped with N (>10 20 cm -3 ) after annealing at 1000°C.…”

Section: Introductionmentioning

confidence: 92%

“…The previous studies [3][4][5][6][7][8][9][10][11][12][13][14] of the contact properties of the NiAl contacts with various compositions for p-and n-type SiC are shown in the ternary NiTiAl compositional diagram of figure 1, where the Ni-Ti-Al compositions which showed ohmic behaviors for p-and n-type SiC are shown by open circles and squares, respectively [15]. The contact properties are strongly influenced by the Al concentrations, and the ohmic contacts for n-and p-type SiC are formed in the contact materials with Al-poor and Al-rich compositions, respectively.…”

Section: Introductionmentioning

confidence: 98%

“…In order to simplify the fabrication process, simultaneous formation of ohmic contacts for both n-and p-type semiconductors using same contact materials and annealing temperature is mandatory, which results in miniaturizing the cell sizes, possibly leading to wide applications for the SiC devices. Although a variety of the ohmic contact materials to SiC have been developed, only a few materials are suitable ohmic contacts for both n-and p-type SiC [3][4][5]. Fursin et al [3] reported that a nickel contact, which was known as a typical ohmic contact material for n-type SiC [6], showed ohmic behavior after annealing at 1050 °C for both n-and p-type SiC implanted with nitrogen and aluminum at the levels of the order of 10 19 and 10 21 cm -3 , respectively.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Formation of Ohmic Contacts for Both N- and P-Type 4H-Sic Using Nial-Based Contact Materials

et al. 2006

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In order to simplify a fabrication process of silicon carbide power MOSFETs (metal oxide semiconductor field effect transistors), development of a simultaneous formation process of ohmic contacts to both the p-well and n-source regions of the SiC devices using same contact materials and one step annealing was challenged. We succeeded to develop NiAl-based contact materials which provided ohmic behaviors for both n-and p-type 4H-SiC after one step annealing. The Ni/Al and Ni/Ti/Al ohmic contacts were prepared by depositing sequentially Ni, (Ti) and Al layers with various layer thicknesses onto the n-and p-type SiC substrates which were doped with N at 1×10 19 cm -3 and with Al at 8×10 18 cm -3 , respectively. The Ni(50 nm)/Al(5 ~ 6 nm) contacts showed ohmic behaviors for both the n-and p-type SiC substrates after annealing at 1000 ˚C. The Ni(20 nm)/Ti(50 nm)/Al(50 ~ 70 nm) contacts showed ohmic behaviors for both the n-and p-type SiC substrates after annealing at a lower temperature of 800 ˚C. The specific contact resistances of these contacts were measured to be in the order of 10 -3 Ω-cm 2 for both p-and n-type SiC, and were found to have strong dependence of the Al layer thicknesses of materials. The interfacial microstructures of the NiAl-based contacts were also observed by transmission electron microscopy (TEM) to understand the current transport mechanism through the metal/SiC interfaces.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Simultaneous Formation of Ohmic Contacts for Both N- and P-Type 4H-Sic Using Nial-Based Contact Materials

et al. 2006

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“…Kiritani et al 20 demonstrated a 4H-SiC vertical MOSFET with a single material contacts to the n + source region, the p well contact and the polysilicon gate. The n + source and p + contact regions were fabricated by phosphorous and aluminium ion implantation, followed by an annealing at 1600°C for dopant activation.…”

Section: New Trends In Ohmic Contacts For Practical Devicesmentioning

confidence: 99%

“…19: Specific contact resistance as a function of the Al atomic percent in single-metal Al/Ni contacts for the n* source region, the contact of the p-well, and the poly Si gate in 4H-SiC MOSFETs (Data from Ref. [20]). The optimal values of p c were obtained for an Al atomic percent of 6%.…”

Section: New Trends In Ohmic Contacts For Practical Devicesmentioning

confidence: 99%

Ohmic Contacts To

Roccaforte¹,

Via²,

Raineri³

2006

Sic Materials and Devices

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In this chapter, the most significant results obtained in the last decade in the field of ohmic contacts to SiC are reviewed. First, the basic concepts related to the physics of ohmic contacts and to the contact resistance measurement techniques are briefly reported. Then, some aspects concerning the formation of low resistance (10~5-10~6 £2cm 2 ) ohmic contacts on n-type and for p-type SiC are discussed, focusing on Ni-based and Al/Tibased contacts. Examples of innovative applications on practical devices are also reported, as the simultaneous formation of ohmic contacts on n-and p-type SiC for vertical power MOS devices, obtained adding Al to a standard Ni contact, and a single-metal technology for ohmic and rectifying contacts in MESFETs, using Ti or Ni without post-deposition annealing.

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Silicon Carbide Junction Field‐Effect Transistors (SiCJFETs)

Veliadis

2014

Wiley Encyclopedia of Electrical and Electronics Engineering

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Wide bandgap semiconductors like silicon carbide (SiC) are currently being developed for high‐power/high‐temperature applications. Silicon carbide (SiC) is ideally suited for power switching because of its high saturated drift velocity, its high critical field strength, its excellent thermal conductivity, and its mechanical strength. For power devices, the 10‐fold increase in critical field strength of SiC relative to Si allows high‐voltage blocking layers to be fabricated significantly thinner than those of comparable Si devices. This reduces device ON‐state resistance and the associated conduction and switching losses, while maintaining the same high‐voltage blocking capability. The specific ON‐state resistance of 4H‐SiC is approximately 400 times lower than that of Si at a given breakdown voltage. This allows for high current operation at relatively low forward voltage drop. In addition, the wide bandgap of SiC allows operation at high temperatures where conventional Si devices fail. In this article, we will review the SiC single‐implant no epitaxial regrowth vertical channel junction field‐effect transistor (JFET). The feasibility of efficient 1200 V normally OFF JFET operation will be investigated. The all‐SiC JFET‐based cascode switch will be introduced and aspects of its operation evaluated. High‐temperature direct‐current (dc) characteristics of JFETs and 1200 V normally OFF cascode switches will be discussed. Large‐area high‐current JFETs and their current sharing and switching performances will be presented. Aspects of JFET fabrication, including their edge termination, will be provided. JFET wafer yields and parameter uniformities will be presented. Hard and unclamped inductive JFET switching evaluations will be introduced. Finally, a 9‐kV JFET will be introduced and its reliability under bipolar stress will be examined.

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Single Material Ohmic Contacts Simultaneously Formed on the Source/P-Well/Gate of 4H-SiC Vertical MOSFETs

Cited by 17 publications

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Simultaneous Formation of Ohmic Contacts for Both N- and P-Type 4H-Sic Using Nial-Based Contact Materials

Simultaneous Formation of Ohmic Contacts for Both N- and P-Type 4H-Sic Using Nial-Based Contact Materials

Ohmic Contacts To

Silicon Carbide Junction Field‐Effect Transistors (SiCJFETs)

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