An investigation of species dependence in germanium pre-amorphized and laser thermal annealed ultra-shallow abrupt junctions

Abstract

An earlier study of the activation and deactivation characteristics of p- and n-type dopant materials in shallow pre-amorphized silicon layers showed varying melt depth for a constant laser energy with varying dopant species. Possible causes of this variation could be attributed to either laser repeatability issues on early test equipment or a species-related laser absorption effects. Species dependence process windows are of serious concern for minimizing process complexity in CMOS wafer manufacturing. This paper reports the results of an investigation into the dependence of laser annealed junction depth in germanium pre-amorphized silicon layers on varying doses of boron, arsenic: and phosphorus dopant species. A 10 keV, 1/spl times/10/sup 15/ ions/cm/sup 2/ germanium implant was used to amorphize the silicon surface and set the laser annealed junction depth. Low energy implantation was used to introduce 1 keV boron, 2 keV phosphorus and 5 keV arsenic at doses of 1/spl times/10/sup 15/ and 3/spl times/10/sup 15/ ions/cm/sup 2/ into the amorphous region. Laser thermal annealing was performed at energies from 0.3 to 0.68 J/cm/sup 2/. Four-point probe and secondary ion mass spectrometry analysis data are presented.