Boron in mesoporous Si - Where have all the carriers gone?

Highly-doped p-type Si is electrochemically etched in an HF-based electroly te to produce mesoporous surface layers. Using both elastic-recoil detectio n analysis and secondary ion mass spectroscopy it is concluded that B atoms are not removed from the porous layer. Crystallite size for the most porou s samples is related to the average dopant spacing. It is argued that the e lectrolytic erosion of Si stops when B is in the surface layer and passivat ed. (C) 1999 Elsevier Science B.V. All rights reserved.