A low-temperature thermal ALD process for nickel utilizing dichlorobis(triethylphosphine)nickel(ii) and 1, 4-bis(trimethylgermyl)-1, 4-dihydropyrazine. Issue 29 (6th July 2022)

• Record Type: Journal Article
• Authors: Vihervaara, Anton; Hatanpää, Timo; Mizohata, Kenichiro; Chundak, Mykhailo; Popov, Georgi; Ritala, Mikko
• Is Part Of: Dalton transactions. Volume 51:Issue 29(2022)
• Page Start: 10898
• Page End: 10908
• Publication Date: 2022-07-06
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt01347a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Novel precursors enable the low-temperature ALD of metallic nickel thin films. Abstract : In this work, we developed a new ALD process for nickel metal from dichlorobis(triethylphosphine)nickel(ii ) (NiCl2 (PEt3 )2 ) and 1, 4-bis(trimethylgermyl)-1, 4-dihydropyrazine ((Me3 Ge)2 DHP). A series of phosphine adducts of nickel and cobalt halides were synthesized and characterized for their volatility and thermal stability. Also (Me3 Ge)2 DHP is a novel reducing agent in ALD. Smooth nickel films were deposited on different substrate materials at 110 °C, which is the lowest deposition temperature for Ni metal found in the literature. The growth rate is 0.2 Å per cycle when the film is not continuous and decreases to 0.1 Å per cycle after the film becomes pinhole-free. Besides a small amount (7 at%) of carbidic carbon, the films have only small amounts of impurities. Most notably, the chlorine content is below 0.2 at%, indicating efficient reduction. Furthermore, we think that (Me3 Ge)2 DHP can open new avenues for the ALD of other metals at low temperatures.