Characterization of As + ion-implanted layers in strained-Si/SiGe/Si hetero-structures

Abstract

Arsenic ions were implanted in a strained-Si/SiGe/Si hetero-structure to fabricate an n + layer in the substrate. The disordering of the substrate caused by ion implantation and the reordering during post-implant rapid thermal annealing (RTA) were analyzed by Rutherford backscattering and channeling (RBS) measurements. It was shown that the major part of implantation-induced defects was eliminated during RTA for 10 s above 900 °C. Electrical and atomic-concentration profiles for As-implanted layers were examined by differential Hall-effect and secondary ion mass spectrometric (SIMS) measurements, respectively. A 25-nm thick, n + layer with carrier concentrations in a range of 5.2×10 19 to 1.7×10 20 cm −3 was formed in the strained Si layer after RTA at 1000° C without the deterioration in the abruptness of the Si/SiGe interface. It was also revealed that the electrons in the strained Si layer had a higher mobility than the electrons in bulk Si by a factor of around 1.2 in a carrier concentration range of mid-10 19 to -10 20 cm −3.