Undergraduate Thesis

In micro-electronic industry, silicon is the most important semiconductor material. Silicon is dominated as the major material usage of integrated circuits and solar cells fabrication. The process technology for the fabrication of silicon devices is quite complex, including etching, lithography, deposition, doping, surface passivation, etc. Etching technique is a very important process in designing the semiconductor devices. In solar cell manufacture, etching is applied for removing the surface damage and texturing which can help to reduce huge amount of surface reflection of the cell. In addition, etching also can be applied for selective removal of deposited thin film material to leave desired pattern on wafer surface

There are mainly two types of etching methods, wet-etching and dry-etching. Compare with dry-etching, wet-etching takes advantages of high etching rate and lost cost processing. In silicon wet-etching process, there are several kinds of etching solution that is applied for different purpose. Different compositions of solution with different ratios have different etching rates. Moreover, etching rate is also very sensitive with the doping concentration in silicon as well as etching temperature.

This thesis investigates the temperature and doping effects on silicon wet-etching rate. It presents the results from the extensive investigation and study on the chemistry of silicon etching and the mechanism of etching. Base on abundant experimental sampling and research, the effect of doping concentration and etching temperature on silicon wet-etching rate can be concluded.

In order to guarantee consistent wet-etching results, and the improvement of wet etching techniques, future work is required on stabilising and characterisation wet etching process.