Chemical treatment effect of Si(111) surfaces in NH4F solution studied by spectroscopic ellipsometry
Abstract
Chemically treated Si(111) surfaces in NH4F (40%) solution at 20 C have been studied using spectroscopic ellipsometry (SE) and exsitu atomic force microscopy (AFM). The SE data clearly indicate that the solution causes the removal of the native oxide with an etch rate of approx. 15 angstrom/min. Just after the native oxide is etched away completely (t approx. 70 s), the SE data yield the spectrum of a slightly roughened surface. With further etching, the Si surface becomes gradually rougher. The roughened surface thickness immersed for t approx. 600 s, for example, is approx. 16.5 angstrom with a void fraction of approx. 42%, obtained using an effective medium approximation (EMA); the resulting AFM image of this sample indicates a roughened surface of approx. 14 angstrom rms with the emergence of pillars and hollows. It can thus be concluded that SE can be used to assess important chemical treatment parameters of crystalline Si.
- Publication:
-
Japanese Journal of Applied Physics Regular Papers Short Notes and Review Papers
- Pub Date:
- October 1994
- Bibcode:
- 1994JJAPR..33.5599S
- Keywords:
-
- Ammonium Compounds;
- Ellipsometry;
- Etching;
- Semiconductors (Materials);
- Silicon;
- Surface Finishing;
- Surface Roughness;
- Surface Treatment;
- Atomic Force Microscopy;
- Chemical Effects;
- Crystallinity;
- Spectroscopic Analysis;
- Voids;
- Electronics and Electrical Engineering