Macropore Formation on Highly Doped n-Type Silicon

Abstract

Using specially “designed” electrolytes, it is possible to obtain macropores even in highly doped n-type silicon (0.020–0.060 Ωcm) without illumination. Based on predictions of the “current-burst-model” [phys. stat. sol. (a) 182, 63 (2000), this issue], HF-containing electrolytes were systematically modified with strongly oxidizing components and evaluated with respect to their ability to produce macropores. Well developed macropores with depths up to 10 μm and pore diameters between 200 nm and 2 μm could be obtained in several cases. The macropore nucleation starts with a facetting of the surface on {111} planes.