Handbook of Silicon Based MEMS Materials and Technologies

16.3. Resistivity

In order to achieve the desired electrical characteristics, silicon is doped either n-type (As, P, or Sb doping) or p-type (B doping). Typical concentrations of dopant atoms vary from 10¹⁴ cm⁻³ up to 2 × 10²⁰ cm⁻³; that is, from about 2 × 10⁻⁷% to 0.4%. More typically the doping level is given as the corresponding electrical resistivity, which better describes the behavior of the material in electrical circuits. Resistivity is determined by the concentration of mobile charge carriers in the material, as well as their mobility μ (ability to move in an electric field). As shown in Eq. 16.1, the resistivity ρ is roughly inversely proportional to the concentration of the free carriers (n).(16.1)

Here q = unit charge, a constant. ...