Electrical and structural properties of buried CoSi2 layers in Si(100) grown by molecular beam allotaxy

Abstract

Buried, single-crystal CoSi2 layers in Si(100) were fabricated by molecular beam allotaxy, a new two-step method to fabricate buried epitaxial layers. At first CoSi2 precipitates embedded in Si(100) were grown in a molecular beam system. In a second step a continuous, buried silicide layer was formed by rapid thermal annealing. Buried layers with thicknesses ranging from 27 to 224 nm were fabricated and investigated by transmission electron microscopy, Rutherford backscattering, He ion channelling and various electrical methods. Electrical resistivity measurements between 4.2 and 300 K revealed a specific resistivity of 14 μΩ cm at room temperature and 1 μΩ cm at 4.2 K. The temperature dependence follows the Bloch-Grüneisen relation. The resistivity increases with decreasing layer thickness. Schottky diodes were fabricated and characterized using I-V and I-T methods. Excellent diodes were produced with barrier heights of 0.64 ± 0.03 eV and idealities of 1.08.