Macropore formation on highly doped n-type silicon

Using specially "designed" electrolytes, it is possible to obtain macropore s even in highly doped n-type silicon (0.020-0.060 Omega cm) without illumi nation. Based on predictions of the "current-burst-model" [phys, stat. sol. (a) 182, 63 (2000), this issue], HF-containing electrolytes were systemati cally modified with strongly oxidizing components and evaluated with respec t to their ability to produce macropores. Well developed macropores with de pths up to 10 mum and pore diameters between 200 nm and 2 mum could be obta ined in several cases. The macropore nucleation starts with a facetting of the surface on {111} planes.