Biased pulse DC reactive sputtering of oxide films
View Patent ↗A biased pulse DC reactor for sputtering of oxide films is presented. The biased pulse DC reactor couples pulsed DC at a particular frequency to the target through a filter which filters out the effects of a bias power applied to the substrate, protecting the pulsed DC power supply. Films deposited utilizing the reactor have controllable material properties such as the index of refraction. Optical components such as waveguide amplifiers and multiplexers can be fabricated using processes performed on a reactor according to the present invention.
1. A method of forming a waveguide amplifier, comprising:
providing a substrate with an undercladding layer;
providing an RF bias to the substrate;
providing a target having a concentration of rare-earth ions opposite the substrate;
supplying process gas between the target and the substrate;
applying pulsed DC power where the voltage on the target oscillates between positive and negative voltages through a narrow band rejection filter that matches the RF bias to the target to deposit an optically active film;
patterning the film to form a core;
depositing an uppercladding layer over the core.
2. The method of claim 1 , wherein providing a substrate includes providing a silicon substrate with a thermal oxide layer.
3. The method of claim 1 , wherein providing a target includes providing a target having a concentration of up to about 5 cat. % of rare earth ions.
4. The method of claim 3 , wherein providing a target includes providing a target of Al and Si.
5. The method of claim 1 , wherein providing a target includes providing a target with a concentration of Al.
6. The method of claim 5 , wherein providing a target includes providing a target with a concentration of Si.
7. The method of claim 5 , wherein providing a target includes providing a target with a concentration of rare earth ions.
8. The method of claim 1 , further including providing bias power to the substrate.
9. The method of claim 1 , further including scanning a magnet over the target.
10. The method of claim 1 , wherein scanning the magnet over the target includes moving the magnet in a first direction.
11. The method of claim 10 , wherein the magnet extends beyond the target in a second direction perpendicular to the first direction.
12. The method of claim 1 , wherein the target has a surface area greater than the surface area of the substrate.
13. The method of claim 8 , wherein the filter rejects power at a frequency of the bias power.