2.1.3 Thermal Processing

Thermal treatment of the wafer is necessary at multiple stages during a fabrication process. Annealing of the silicon crystal structure is necessary because ion implantation introduces significant damage to the crystal lattice which would cause defect devices. Another need for thermal treatment arises from processing techniques such as local oxidation [103], where dedicated areas of the semiconductor surface are exposed to an ambient gas which causes the formation of silicon-dioxide material used for isolation purposes. The underlying physical phenomena are quite complex and, therefore, various physical models have been developed and implemented so far.