Atomic Layer Deposition and Direct-Liquid-Injection Chemical Vapor Deposition of Nickel Nitride Films and Their Conversion to Nickel Silicide Films.

摘要

Nickel silicide (NiSi) is considered as one of the key materials for source and drain contacts in future semiconductor devices. The development of atomic layer deposition (ALD) and direct-liquid-injection chemical vapor deposition (DLI-CVD) processes for nickel (Ni) films is important for the formation of NiSi, because these processes can provide uniform film thickness inside narrow and complex features needed in future microelectronic devices.;ALD of Ni films with various co-reactants is investigated in Chapter 2. The films are deposited from an amidinate precursor, bis(N, N'-di-tert-butyl-acetamidinato)nickel(II) (Ni(MeC(N tBu)2)2), with water, formic acid and ammonia (NH3) as the co-reactant, respectively. Among these processes, the ALD of NiNx films turns out to be optimal way for the growth of Ni.;DLI-CVD processes of NiNx films are studied in Chapter 3. The films are deposited using a solution of Ni(MeC(NtBu) 2)2 in tetrahydronaphthalene and either NH3 or a mixture of NH3 and hydrogen (H2) gases as the co-reactant. These films have nearly 100% step coverage in high-aspect-ratio (>50:1) holes. Annealing of the films in H2 at 160°C or hydrogen plasma treatment at room temperature removes the nitrogen and leads to pure Ni films.;The conversion of the DLI-CVD NiNx films to NiSi films is studied in Chapter 4. Rapid thermal annealing (RTA) of the films with thickness larger than 20 nm leads to the formation of continuous NiSi films at temperatures above 400°C. In situ annealing and Ti capping methods have been developed for the formation of NiSi from thinner NiNx films in order to avoid oxygen diffusion and the agglomeration of the films. In situ silicidation experiments are carried out for high-N-content NiNx films on (100), (110) and (111) Si and trench structures. Uniform NiSi films can be formed along trench structures by well controlled experimental conditions.