Spike Annealing as Second Rapid Thermal Annealing to Prevent Pure Nickel Silicide From Decomposing on a Gate

Stress-induced voiding in nickel silicide

“…This indicates that the disconne ctions occurred after the silicon nitride film for the upper layers of the interconnec t was deposited. In other words, the disconnections did not occur during silicidation annealing; therefore, they were not due to hillock degradation, as previousl y reported [10]. These findings suggest that the disconnections were due to stress-induced voiding in the Ni-Pt silicide due to the thermal budget of the interconnec t fabrication.…”

“…200-350°C and into monosilicide during a second RTA (RTA2) at ca. 350-600°C [8,10,17]. First, in situ chemical dry-clean ing [18,19] was performed before Ni-Pt sputtering with a collimator.…”

“…However, NiSi film has hillocks caused by its thermal instability. These hillocks can be created by anomalous growth into nickel di-silicide (NiSi 2 ) [8], agglomerati on of NiSi [9], or decompositi on into di-nickel silicide (Ni 2 Si) [10]. To prevent hillock degradation , platinum incorporated NiSi was applied [11,12].…”

“…In one, a partial conversion of Ni-Pt alloy is applied as the initial silicidation process to suppress NiSi 2 formation even between gates [13][14][15][16]. In the other, a rapid thermal annealing (RTA) in instantaneo us time is applied as the second silicidation process to suppress the agglomeration of the NiSi or its decompo sition into Ni 2 Si [10].…”

Structural changes during the reaction of Ni thin films with (100) silicon substrates

“…7 and 8). Previous studies have shown complete consumption of thin nickel films in contact with an Si substrate to form nickel silicides after rapid thermal annealing to 850°C [33][34][35]. During the in situ annealing experiments presented in this study, the formation of NiSi 2 crystallizing in the CaF 2 structure occurred at 280°C for the thinner film and 500°C for the thicker film.…”