Titanium-Based Ohmic Contact on p-Type 4H-SiC

Cho, Nam Ihn; Lee, J.H.; Yang, Shou Jie; Kim, C.K.; Lee, Byung Teak; Rim, Kwan; Kim, Nam Kyun; Kim, Eun Dong

doi:10.4028/www.scientific.net/msf.389-393.913

Cited by 9 publications

(2 citation statements)

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“…In the production of a wide variety of 4H-SiC electronic devices, low resistance, reproducible and stable ohmic contacts to the semiconductor material are of great necessity. A number of different metals have been proposed as suitable ohmic contact materials [1][2][3][4]. Lowing the Schottky barrier height between the contact metal and substrate, or increasing the doping level of the substrate, has been used to decrease the contact resistance.…”

Section: Introductionmentioning

confidence: 99%

Improved ohmic contact to the n-type 4H-SiC semiconductor using cobalt silicides

Cho

Jung

Choi

2003

Semicond. Sci. Technol.

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Multilayer structures of cobalt and silicon have been deposited as an ohmic contact on n-type 4H-SiC substrates in order to obtain lower contact resistance and higher thermal stability. The metal structures were prepared by using electron beam evaporation on top of the silicon face of the 4H-SiC substrates, and were annealed in an atmosphere of argon with 10% hydrogen. The metal film thickness was monitored during the film deposition, and the ratio of the cobalt and silicon was fixed at 0.5 for the formation of the silicon-rich silicide structure (CoSi 2 ). The electrical property of the ohmic contact has been significantly improved by the reduction of the oxide content in the metal contact layer. A two-step annealing process was employed to reduce oxidation problems that may occur in the heat treatment at high temperatures. The specific contact resistance of the contact structure prepared by the two-step annealing process was measured to decrease by more than one order of magnitude compared to that prepared by one-step annealing. The best result has been obtained as 1.8 × 10 −6 cm 2 for Co/Si/Co/Si/Co metal structures after two-step annealing, at 500 • C for 600 s and 800 • C for 120 s. In the field emission scanning electron microscopy, the interface of the contact structure and SiC substrate was observed to have smooth surface morphology with CoSi 2 grains.

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Section: Introductionmentioning

confidence: 99%

Improved ohmic contact to the n-type 4H-SiC semiconductor using cobalt silicides

Cho

Jung

Choi

2003

Semicond. Sci. Technol.

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“…In order to overcome this problem, covering layers of noble or nearly noble metals (Pt, Co) can be deposited onto the Ti layer. 96 Moreover a diffusion barrier can be also deposited between the two metals to avoid intermixing which may cause an increase of the contact resistivity. Co/Ti contacts onto p-type Al-doped (N A =3.9xl0 18 cm" 3 ) 4H-SiC exhibited an encouraging value of the specific contact resistance (4xl0~4 Qcm 2 ) after annealing at 850°C.…”

Section: Alternatives To Al/ti Contactsmentioning

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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