Kinetics of processes in the Ti–Si1−xGex systems

Abstract

The kinetics of processes related to the formation of C49 and C54 Ti(Si1−yGey)2 germanosilicide phases in the two relaxed and strained Ti/Si1−xGex systems (x1=0.35 and x2=0.20) in the temperature range 600–800 °C are considered. These processes have been studied through Auger electron spectroscopy, secondary ion mass spectroscopy, x-ray diffraction, and Raman scattering spectroscopy supported by ion beam etching techniques. Si/Ge ‘‘intergrain’’ alloy has been found between the grains of the C49 or/and C54 phases, with a Ge-rich part Si1−zGez of z=2x–3x in the upper region. At higher temperatures, the Ge concentration in the Ge-rich alloy decreases and its volume increases. The temperature required for obtaining similar changes are higher when x2<x1. A kinetic electron-related model is proposed to explain the observed phenomena.

Effects of composition on the formation temperatures and electrical resistivities of C54 titanium germanosilicide in Ti–Si1−xGex systems

“…37 This model takes into account the significant influence of electronic processes on atomic diffusion and materials transformation. Consequently, the metal layer contacted with the semiconductor can cause a drastic acceleration of atomic diffusion and material transformation at the metal-semiconductor interface.…”

“…36 As a result, the Ti layer on the top of the Si 1Ϫx Ge x alloy can enhance considerably the atomic diffusion. Freiman et al 37 invoked the model and showed a good correlation among activation energy, diffusion coefficient, nucleation time, and Ge concentration. Higher temperatures are required for samples containing a lower concentration of Ge to realize the same degree of material transformation.…”

Pulsed KrF laser annealing of Ni/Si0.76Ge0.24 films

“…1,2 The formation of metal/Si 1Ϫx Ge x ohmic or rectifying contacts are required for the device applications. Thus, the interfacial reactions between some metals such as Ni, 3 , Pt, 4,5 Pd, 5,6 Ti, [7][8][9][10][11][12] Co, 13-16 on Si 1Ϫx Ge x films have been studied. In these reactions the formation of a ternary phase was generally accompanied by Ge segregation.…”

Interfacial reactions of Co/Si0.76Ge0.24 and Co(Si0.76Ge0.24)/Si0.76Ge0.24 by pulsed KrF laser annealing

“…1,2 The formation of metal-Si 1−x Ge x ohmic or rectifying contacts is required for the device applications. Recently, the interfacial reactions of metals such as Ni, 3 Pt, 4,5 Pd, [5][6][7] Ti, [8][9][10][11][12][13] Co, [14][15][16][17] W, 18 Cr, 19 and Cu 20 with Si 1−x Ge x films by conventional furnace annealing have been studied. In these reactions, the formation of a ternary phase, e.g., M(Si 1−x Ge x ) 2 , Ge segregation out of the germanosilicide, strain relaxation of the unreacted Si 1−x Ge x film, and the occurrence of agglomeration structure at higher annealing temperatures were generally observed.…”

“…The superior annealing condition was searched to effectively suppress or improve the phenomena, i.e., Ge segregation out of the germanosilicide, the formation of agglomeration structure, and the occurrence of strain relaxation in the unreacted Si 1−x Ge x film, which were generally observed on vacuum annealing. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In addition, to alleviate the constitutional supercooling phenomenon occurring during laser annealing, the Co(Si 0.76 Ge 0.24 )/Si 0.76 Ge 0.24 system was simultaneously studied because it was reported 23 that interfacial instability and cell formation can be suppressed by melting monosilicide or disilicide films.…”