Specific Process Knowledge/Thin film deposition/Deposition of Silicon Oxide

Deposition of Silicon Oxide can be done with either LPCVD, PECVD or by sputter technic. You can also make a silicon oxide layer by growing a thermal oxide in a hot furnace but that requires a silicon surface as a starting point.

Deposition of Silicon Oxide using LPCVD

The LPCVD oxide you can deposit at DANCHIP is called TEOS oxide. It can be made in the LPCVD TEOS furnace. It is a batch process meaning you can run a batch of 25 wafers at a time. The deposition takes place at temperatures of 700? degrees Celsius. The TEOS oxide has a good step coverage and the film thickness is very uniform over the wafer?. We have two standard TEOS processes: One for depositing ? and one for deposition ?.

Deposition of Silicon Oxide using PECVD

PECVD oxide can be deposited in one of the PECVD systems. You can run 1-3 wafers at a time depending on which one of the PECVD's you use. The deposition takes place at 300 degrees Celcius. This can be of importance for some applications but it gives a less dense film and the oxide is expected to have some hydrogen incorporated. The step coverage and thickness uniformity of the film is not as good as for the LPCVD TEOS oxide. PECVD oxide has excellent floating properties when doped with boron and/or phosphorus. Then it can be used ex. as top cladding for waveguides or encapsulation of various structures/components. In one of our PECVD systems (PECVD3) we allow small amounts of metal on the wafers entering the system, this is not allowed in the LPCVD and in the other PECVD (PECVD1). It is also a possibility to dope the silicon oxide with Germanium for altering the refractive index of the oxide.