Cobalt and nickel atomic layer depositions for contact applications

Abstract

Novel NH 3 -based Co thermal atomic layer deposition (T-ALD) process using Co(iPr-AMD) 2 (bis(N,N′-diisopropylacetamidinato)cobalt(II)) and NH 3 as a precursor and a reactant, respectively, was developed for nanoscale contact applications. The T-ALD Co films showed high purity with perfect conformality inside nanosize contact holes. By annealing the T-ALD Co films, CoSi 2 was obtained. Similarly, Ni T-ALD process using NH 3 as a reactant was also investigated by using Ni(dmamb) 2 (bis(dimethylamino-2-methyl-2-butoxo)nickel) and Ni films showed perfect conformality of T-ALD Ni.

Area Selective Chemical Vapor Deposition of Metallic Films using Plasma Electrons as Reducing Agents

“…For instance, iron oxide films can be deposited at temperatures ranging from 150 °C to 500 °C by thermal ALD [36][37][38][70][71][72], and by PEALD [73]. Cobalt and nickel films can be deposited at temperatures ranging from 125 °C to 350 °C by thermal ALD [41,[74][75][76][77][78], and PEALD [39,[79][80][81]. However, issues such as precursor decomposition (i.e., CVD growth) and the loss of the characteristic self-limiting component of ALD, have been reported in many of these processes.…”

Atomic Layer Deposition of Cobalt Silicide Thin Films Studied by in Situ Infrared Spectroscopy

“…1,2 Moreover, materials with low contact resistance and good compatibility with silicon processing are crucial to device scaling. 3 Several silicide materials have already been implemented in silicon technology, such as WSi 2 , 4−6 TaSi 2 7−9 and MoSi 2 , 10,11 but they are difficult to grow by direct reaction with silicon.…”

“…In the microelectronics industry, there is a need to deposit silicide films as contact materials alternative to titanium silicide (TiSi 2 ) to mitigate narrow line-width effect issues. , Moreover, materials with low contact resistance and good compatibility with silicon processing are crucial to device scaling . Several silicide materials have already been implemented in silicon technology, such as WSi 2 , − TaSi 2 − and MoSi 2 , , but they are difficult to grow by direct reaction with silicon.…”

“…For direct silicide deposition, different techniques are used, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Although PVD is most commonly used, it suffers from limited step coverage, leading to poor conformality, especially in deep contact holes. ,, CVD has also been used for some materials (e.g., WSi 2 ), , but the conformality of CoSi 2 films is necessary to minimize the consumption of Si and avoid the degradation of pn junctions and still cannot be achieved with CVD. Consequently, atomic layer deposition (ALD), through its sequential and self-limiting surface reactions, is most attractive to deposit silicides due to its simplicity, reproducibility, and the high conformality of the resulting films .…”