and Their Uses:
As design rules shrink to the
sub micron range for MOS VLSI it becomes increasingly important to grow oxides
on crystalline silicon in 50 to 200°A ranges
in a repeatable way. 
- Ultra thin oxide (<50 °A) has been produced using
hot nitric acid, boiling water and air at room temperature.
- Rapid thermal oxidation performed in
controlled oxygen ambient with heating provided by tungsten-halogen lamps
have also been used to grow thin oxides (40-130°A).
Some factors, which affect thin
oxide growth, are as follows:
- Cleaning techniques used
- Purity of gases used
- Thickness of the oxide