Charakterisierung und Optimierung der Materialeigenschaften von porösem Silicium für aktive und passive optische Bauelemente

The aim of this work was to explore the boundaries of porous silicon to make a broader range of applications of the material possible. The special attention of the work was focused an the possibility to apply porous silicon in optical devices. The porous layers and layersystems have been characterized with gravimetric, spectroscopic and electric methods as well as with a Scanning Electron Microscope. Due to the supercritical drying process it was possible to fabricate porous layers with porosities near to 100 % which were still mechanically stable. The changed thermal and optical properties of the porous layers have been determined and rated. The special problems of the long term stability of porous silicon with it huge inner surface in humid atrnospheres have been solved by a chemical modification of the surface. The long term stability of samples treated with this method were tested against es prepared and common oxidized samples in atmospheres with a humidity up to 100%. A new method to influence the etch-rate of electrochemical etch processes was developed. It has been shown, that different etch-rates can be deduced from one etch process. Continuous and discrete variation of the etch-rate is possible