Phosphorus doping reactions with silicon

Eqs. (6.69) and (6.70) are the doping reactions related to the gas-phase and solid-phase concentrations of silicon and phosphorus. The square root law applies to the gas-phase arsenic concentration provided that and are regular (i.e. independent of arsenic concentration). However, the law only applies to the solid-phase concentrations (Eq. (6.70)) if, in addition, is also constant. The variation of the arsenic distribution coefficient with rf power and gas concentration (Fig. 5.4) explains the deviations from the doping law for the solid phase which are shown in Fig. 5.17. The phosphorus distribution coefficient has a much weaker dependence on the rf power and gas concentration, so... 

The thermodynamics of doped a-Si H is a little more complicated, because both the defects and dopants are charged and so interact with the electron distribution whose chemical potential is the Fermi energy. The analysis is for the specific case of n-type doping with phosphorus and, following the model introduced in Chapter 5, it is assumed that both the phosphorus and sUicon atoms may have either three-fold or four-fold coordination. The ground state configuration comprises the four-fold silicon and the three-fold phosphorus, and the defect reaction is,... 

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