Thin buried cobalt silicide layers in Si(100) by channeled implantations

Abstract

Si(100) wafers have been implanted with 50 keV Co ions at elevated substrate temperatures (320 °C) in the dose range 7.8×1014–7.8×1016 at. cm−2. A comparison is made between channeled (along the Si 〈100〉 surface normal) and random (tilted by 7°) implantations. Co depth distributions are measured with secondary-ion mass spectrometry and compared to marlowe and trim simulations. Annealed samples are characterized by Rutherford backscattering spectrometry and transmission electron microscopy. Our data indicate that for channeled implantations the sputtering effect is strongly reduced as compared to random implantations. Also, the average penetration depth is increased by about 20%. As a consequence, annealing of our high-dose implanted samples yields either a discontinuous surface silicide layer (random case) or a pinhole-free buried silicide layer (channeled case).