Thermal stability and electrical properties of Zr/Si1−x−yGexCy contacts after rapid thermal annealing

Abstract

In this work, we have investigated the reaction between Zr and SiGeC alloys. Annealings have been performed in a rapid thermal annealing (RTA) furnace at temperatures ranging from 400 to 800 °C for 5 min. The reaction of the metal with the alloy has been investigated by x-ray diffraction and Rutherford backscattering spectrometry. Four crystal x-ray diffraction was performed to measure the residual strain in the epilayer. The analyses indicate that the C49-Zr(Si1−xGex)2 is the final phase of the reaction. For all compositions examined (from 0% up to 33% of Ge), the C49 film has the same Ge content as in the as-deposited Si1−x−yGexCy layer and no Ge segregation has occured. In addition, this thermal treatment leads to only a small strain relaxation in the unreacted epilayer. The presence of C does not modify the reaction and it prevents any strain relaxation. Schottky barrier height measurements have been performed on p-type layers. RTA leads to a slight decrease of the barrier without any degradation of the contact. The C49 film presents a resistivity of about 80 μΩ cm. These results indicate that Zr may be a good candidate for contacts on IV–IV alloys in terms of thermal stability.

Annealing of thin Zr films on Si 1−x Ge x (0≤ x ≤1): X-ray diffraction and Raman studies

“…In the Zr-SiGe system, the absence of Ge segregation during the Zr germanosilicide formation is usually explained by a reduced mobility of Si and Ge compared with the C54 Ti(Si 1-y Ge y ) 2 and by a lower thermodynamic driving force for Ge segregation in the Zr-SiGe system than in the Ti-SiGe system. Other studies concerning the electrical properties and thermal stability of the Zr phases formed in the Zr-Si 1-x-y Ge x C y system after rapid thermal annealing have been reported [9][10]. Similar phase sequences have been obtained upon annealing, with C49 Zr(Si 1-x Ge x ) 2 as the final phase of the reaction at 800°C.…”

Interfacial reactions and electrical properties of Hf/p-Si0.85Ge0.15

“…1,2 The formation of metal-Si 1-x Ge x ohmic or rectifying contacts is required for the device applications. 17,[25][26][27][28] The smaller difference in the heat of formation between Zr-Si and Zr-Ge, 5 kJ/mol, 29 may explain the better resistance to Ge segregation in the Zr/Si 1-x Ge x system. In most of these reactions, Ge segregation out of the germanosilicide associated with strain relaxation of the unreacted Si 1-x Ge x film and the occurrence of agglomeration at higher annealing temperatures were generally observed.…”