Synthesis of TiN, Ti and TiSi$_{2}$ thin films for the contact system of solar cells

The influence of deposition parameters, such as: the magnetron power in the range 690–1400 W, the silicon substrate temperature 23–170$^{\circ}$C, the N$_2$ gas flow rate 0.9–3.6 L/h, the Ar gas flow rate 0.06–3.6 L/h, the ratio of N$_2$/Ar gas flows 1–60 on the thickness, the density, and the composition of the deposited films is analyzed. The maximum density 5.247 g/cm$^3$ corresponding to the TiN$_{0.786}$ = Ti$_{56}$N$_{44}$ composition has been achieved at the following deposition parameters: 1200 W, N/Ar = 1.8/0.06 L/h = 30, 0.8 Pa, 320 s, and 100$^{\circ}$C. At temperatures 700–800$^{\circ}$C, the mutual diffusion of titanium and silicon atoms through the interface leads to the active nucleation, the formation of nanocrystals and low-resistance metallization layers. X-ray diffraction shows that, during annealing at 700$^{\circ}$C (30 min, Ar), the formation of phase TiSi$_2$ due to the diffusion of Ti atoms into silicon is twice more intense than the formation of Ti$_5$Si$_3$ due to the diffusion of silicon atoms into titanium as a result of high hardness of titanium. The average sizes of TiSi$_2$ decreases from 7.1 to 5.6 nm at 750$^{\circ}$C due to the crystallization of the nuclei and increase to 9.2 nm at 800$^{\circ}$C.