Investigations on Ni-Ti-Al ohmic contacts obtained on p-type 4H-SiC

Farah Laariedh (1) , Mihai Lazar (1) , Pierre Cremilleu (2) , Jean-Louis Leclercq (3) , Dominique Planson (1)

1 EE - Ampère, Département Energie Electrique
2 INL - Nanolyon - INL - Plateforme Technologique Nanolyon
3 INL - Photonique - INL - Nanophotonique

Transfer Length Method (TLM) based-structures were fabricated on 0.8 µm-thick epitaxial p-type Silicon Carbide (4H-SiC) layers. TLM mesas were defined by a 2 µm height using an SF 6 /O 2 reactive ion etching. TLM metal patterns were obtained by a lift-off procedure and electron beam deposition of Ni, Ti, Al and Pt. The patterned samples were annealed in Argon ambient at temperature ranging from 700°C up to 1000°C in a RTA furnace with a rapid heating ramp (up to 50°C/s) to complete the ohmic contact with the p-type SiC layer. Specific contact resistances were extracted from current/voltage measurements. To identify and follow the profile evolution of constituting element in the contacts and at the SiC/contact interface, the ohmic contacts were characterized using Secondary Ion Mass Spectrometry and Energy-Dispersive X-Ray spectroscopy before and after annealing. Ohmic contacts are obtained only for the Ni/Ti/Al and Ni/Ti/Al/Ni stacking layers and not for the Ti/Al/Ti/Ni and Ti/Al/Ti/Pt/Ni compositions. The specific contact resistance of Ni/Ti/Al/Ni stacking layers was observed to decrease from 2.7×10-4  .cm 2 at 700°C and 6.3×10-5 .cm 2 at 750°C to a minimal value of 1.5×10-5  .cm 2 at 800°C. Ohmic contacts are obtained with a reproducibility of 80 %.

Mots clés: Silicon Carbide; Ohmic contact resistance; Nickel; TLM; SIMS; EDX

Domaines: Energie électrique

Farah Laariedh, Mihai Lazar, Pierre Cremilleu, Jean-Louis Leclercq, Dominique Planson. Investigations on Ni-Ti-Al ohmic contacts obtained on p-type 4H-SiC. HeteroSiC & WASMPE 2011, Jun 2011, Tours, France. pp.169-173, ⟨10.4028/www.scientific.net/MSF.711.169⟩. ⟨hal-00661507⟩