Study of Co- and Ni-based ohmic contacts to n-type 4H-SiC

Investigation of a Self-Aligned Cobalt Silicide Process for Ohmic Contacts to Silicon Carbide

“…27 One of the motivations for the multilayer silicon/cobalt depositions was to reduce the amount of released carbon. 15,[21][22][23] The 40 nm cobalt was motivated by the need to have strong XRD signals. A few substrate pieces (set 1) had only 10 nm cobalt, which was used in XRD and scanning electron microscopy (SEM).…”

“…As such, the CoSi x /4H-SiC system could instead give low resistance ohmic contacts to n-type 4H-SiC, just like the Ni 2 Si/4H-SiC system. CoSi 2 /4H-SiC, formed by multilayer deposition of silicon and cobalt, has been previously studied and been shown to provide low resistance ohmic contact to n-type 4H-SiC, [21][22][23] and the result to p-type 4H-SiC is unclear. 24 We investigated the CoSi x /4H-SiC system to answer the following two research questions 25 :…”

“…The difference from previous contact studies to 4H-SiC is that only cobalt is deposited instead of the silicon/cobalt multilayer stacks. [21][22][23] Moreover, interface reactions between cobalt and 4H-SiC are studied using rapid thermal processing (RTP) to anneal cobalt/4H-SiC instead of furnace annealing cobalt/6H-SiC. 26,27 The annealing temperature range was limited in this study up to 1000 C. It was considered that any contact process requiring higher annealing temperatures than 1000 C would not be competitive with already established contact processes.…”

“…26,27 The annealing temperature range was limited in this study up to 1000 C. It was considered that any contact process requiring higher annealing temperatures than 1000 C would not be competitive with already established contact processes. 2,3,[21][22][23][28][29][30] Higher anneal temperatures could potentially degrade other device related properties, like the silicon dioxide (SiO 2 )/4H-SiC interface of metal oxide semiconductor field-effect transistors (MOSFETs).…”

Radiation effects on ohmic and Schottky contacts based on 4H and 6H-SiC

“…So far, many different metals have been used as both ohmic and SC material such as Ni, Al, Co, Ti, Au and W. In addition, because of its superior advantages such as refractory nature, producing low ohmic contact resistivity [3][4][5][6][7][8][9][10][11] and high SBH [12][13][14][15], Ni has been generally chosen as the contact material both for ohmic and SCs in SiC [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The effects of high-energy proton irradiation and highdose gamma ray irradiation on 4H-SiC Schottky rectifiers have been investigated by Nigam et al and Kim et al respectively, [17,18].…”