HYDROGEN UPTAKE INTO SILICON FROM AN ELECTRON-CYCLOTRON-RESONANCE PLASMA

The concentration of hydrogen in solution near the surface of silicon exposed to an cyclotron resonance (ECR) plasma was determined by measu ring the flux of hydrogen permeating to subsurface microcavities. The energy and flux of hydrogen impinging onto the surface from the plasma was also measured. A model is described which predicts the concentrat ion of hydrogen in solution from the energy and flux of the impinging hydrogen. The measured solution concentrations were approximately 10(- 9) H/Si at 600-degrees-C and approximately 10(-8) H/Si at 400-degrees- C, in fairly good agreement with the model. The absence of accumulatio n of immobile hydrogen near the surface indicates that lattice defects , which strongly trap hydrogen, were not produced by the ECR plasma. T his study establishes a connection between the properties of the ECR p lasma and the concentration of mobile hydrogen in silicon samples expo sed to the plasma, which allows improved control over passivation of d efects and dopants.