EVIDENCE FOR HYDROGEN INCORPORATION DURING POROUS SILICON FORMATION

The incorporation of hydrogen into Si, under different electrochemical conditions including anodization in fluoride solutions where porous s ilicon is formed, is studied by NRA and in situ capacitance measuremen ts. Results suggest a large near surface concentration of H whilst sim ulation show that the maximum penetration depth is governed by volume diffusion of H and material removal. Diffusion coefficients are found to be dependent on electrochemical conditions and ranged between 10(-1 3) and 10(-11) cm(2) s(-1). The interplay of H permeation with porous silicon layer formation is discussed. (C) 1995 American Institute of P hysics.