Effect of germanium pre-amorphization on solid-phase epitaxial regrowth of antimony and arsenic ion-implanted silicon

Abstract

Shallow, low-resistive n +/p junction was investigated for sub 100-nm metal-oxide-semiconductor field-effect transistors (MOSFETs) using antimony and arsenic ion-implantation and low-temperature rapid thermal annealing-increased gate leakage current due to high-permittivity gate dielectric crystallization during high-temperature source and drain dopant activation imposes low temperature annealing for next generation devices. In contrast to arsenic implanted junctions, Sb-doped specimens showed shallower junction depth, lower sheet resistance and leakage current at low temperature processing (600 °C). In addition, Ge pre-amorphization prior to As-implant was used to fully amorphize Si for ideal solid-phase epitaxial regrowth. Pre-amorphized As-doped samples did not result in highly activated junctions at low temperature. Pre-amorphized Sb-doped junctions did not regrow in acceptable annealing time. The results indicated the superiority of antimony to arsenic as a dopant for ultra-shallow and low-resistive source and drain extensions. Arsenic will not be a proper candidate because of higher sheet resistance as a consequence of presence of inactive As-vacancy clusters and higher leakage current for devices that should be fabricated at low temperature with implementing of high- κ dielectric metal-electrode gate stack in next generation MOSFETs.