Mathematical Model of Mechanically Stimulated Changes of Irradiated Silicon Crystals’ Surface Conductivity

Monocrystals of p-Si were used to study the changes in the electrical conductivity of silicon in the course of the action of a single-acting elastic load and X-radiation. An equation describing the dependence of the surface conductivity of irradiated silicon crystals on the amount of elastic deformation (σ) is proposed. This equation made it possible to quantitatively compare the role of the following three radiation-stimulated mechanisms that determine the surface conductivity of p-Si crystals in the course of elastic deformations: (1) reduction of hole mobility (µp); (2) increase of the value of the positive charge in the SiO2 oxidation layer (determined by the factor β1); (3) generation of point defects, which are stoppers for dislocations (determined by the factor β2). If we substitute in the equation for surface conduction the following expressions for a non-irradiated sample: $$\beta_{1} = {1}0^{{{17}}} m^{{ - {2}}} ;\,\beta_{2} \left( \sigma \right) = {1}0^{{{14} }} m^{{ - {2}}} + \sigma \cdot {3}.{51}0^{{7}} Pa^{{ - {1}}} \cdot m^{{ - {2}}} ;\,\mu_{p} \left( \sigma \right) = 0.0{5} m^{{2}} /\left( {V \cdot s} \right) + \sigma \cdot {1}.{5} \cdot {1}0^{{ - {11}}} m^{{2}} /\left( {Pa \cdot V \cdot s} \right),$$ we can get a theoretical curve that almost coincides with the experimental one. By reducing the mobility of holes by 5%, the coefficient β2 by 39%, and by increasing β1 by 4.34%, the theoretical dependence of conductivity on the mechanical load can be obtained for irradiated specimens.