Electrochemical oxidation: Electro chemical oxidation is a process in which silicon is kept in a solution usually water or alcohol, with few other chemicals and another electrode is kept in the same solution. Silicon will be connected to the positive terminal of a battery and the other electrode will be usually platinum electrode and that will be connected to the negative terminal. When this voltage or potential is applied oxygen will form at the silicon electrode and it will react. This will form silicon dioxide and this method is sometimes referred to as anodic oxidation. Usually the silicon dioxide that’s formed here will be very porous and it is of poor quality as far as microelectronic fabrication is considered. However the pore structure and the pore length can be controlled by changing the chemicals as well as the potential and a porous oxide is frequently found useful micro electro mechanical systems that are MEMS and hence the electro chemical oxidation is frequently used in the formation of porous silicon in the MEMS. As far as the semiconductor processing is concerned the chip fabrication, dry oxidation and wet oxidation are the major processes used for oxidizing the silicon. |