FEATURES OF THE INFLUENCE OF THE STRESS STATE ON THE THERMAL STABILITY OF THE NiSi PHASE IN Ni(Pt)/Si FILMS

Background. It is possible to increase the speed, the degree of integration of microcircuits and their reliable operation due to the use of thermostable nanoscale films of transition metal silicides as functional elements. Stress in nanostructures is a general problem of microelectronics, which must be taken into account at all stages of production, storage and operation of both discrete devices and integrated circuits Objective. Study of the effect of stress state and Pt alloying element on the phase composition and thermal stability of NiSi nickel monosilicide in nanoscale [(Ni+1 at.% Pt)30 nm] and [(Ni+8 at.% Pt)30 nm] films on single crystalline Si(001) substrates during vacuum annealing in the temperature range of 400-1000 °С. Methods. Nanoscale films were deposited by magnetron sputtering on Si(001) substrates at room temperature. The samples were annealed in a vacuum of ~1.3∙10-3 Pa in the temperature range of 400-1000 °C. The influence of Pt on the change in stress state and the thermal stability of the NiSi phase in Ni(Pt) films on a single crystalline Si(001) substrate was investigated using the methods of X-ray structural phase analysis, mass spectrometry of secondary neutrals, and resistometry (four-probe method). Results. The influence of internal mechanical stresses and the content of the Pt alloying element in the film on the sequence, temperature of silicide phases formation, and thermal stability of NiSi nickel monosilicide during vacuum annealing was determined. Conclusions. It was established that the addition of Pt to the Ni film leads to an increase in the nickel monosilicide formation temperature compared to the Ni(30 nm) film. Nickel monosilicide NiSi begins to form in films with 1 at.% Pt and 8 at.% Pt during annealing at temperatures of 500 °C and 450 °C, respectively. An increase in the thermal stability of NiSi is associated with a significant decrease in the driving force of the NiSi into NiSi2 phase transition due to the formation of a NixPt1-xSi solid solution, which has a lower free energy, due to the positive contribution of the .