Within this paper, the authors propose a refined high vacuum scanning spreading resistance microscopy (HV-SSRM) electromechanical nanocontact model based on experimental results as well as molecular dynamics (MD) simulation results. The formation under the tip of a nanometer-sized pocket of beta-tin, a metastable metalliclike phase of silicon (also named Si-II), acting as a virtual probe is demonstrated. This gives a reasonable explanation for the superior SSRM spatial resolution as well as for the electrical properties at the Schottky-like SSRM contact. Moreover, the impact of the doping concentration on the plastic deformation of silicon for different species using micro-Raman combined with indentation experiments is studied. In order to elucidate the superior results of SSRM measurements when performed under high vacuum conditions, the impact of humidity on the mechanical deformation and Si-II formation is also analyzed using MD and SSRM experimental results.