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 inention.
1. A method of depositing a film on an insulating substrate, comprising:
providing a process gas between a conductive target and the substrate;
providing pulsed DC power to the target through a narrow band rejection filter such that the target alternates between positive and negative voltages;
providing an RF bias at a frequency that corresponds to the narrow band rejection filter to the substrate;
providing a magnetic field to the target; and
reconditioning the target;
wherein reconditioning the target includes reactive sputtering in the metallic mode and then reactive sputtering in the poison mode.
2. A method of depositing an insulating film on a substrate, comprising:
providing a process gas between a target and a substrate;
providing pulsed DC power to the target through a narrow band rejection filter such that the voltage on the target alternates between positive and negative voltages;
providing an RF bias that corresponds to the narrow band rejection filter to the substrate; and
providing a magnetic field to the target;
wherein an oxide material is deposited on the substrate, and the insulating film is formed by reactive sputtering in a mode between a metallic mode and a poison mode.
3. The method of claim 2 wherein the target is a metallic target and the process gas includes oxygen.
4. The method of claim 2 wherein the target is a metallic target and the process gas includes one or more of a set consisting of N 2 , NH 3 , CO, NO, CO 2 , halide containing gasses.
5. The method of claim 2 wherein the target is a ceramic target.
6. The method of claim 2 wherein the magnetic field is provided by a moving magnetron.
7. The method of claim 2 further including holding the temperature of the substrate substantially constant.
8. The method of claim 2 wherein the process gas includes a mixture of Oxygen and Argon.
9. The method of claim 2 wherein the Oxygen flow is adjusted to adjust the index of refraction of the film.
10. The method of claim 2 wherein the process gas further includes nitrogen.
11. The method of claim 2 wherein providing pulsed DC power to a target includes providing pulsed DC power to a target which has an area larger than that of the substrate.
12. The method of claim 2 , further including uniformly sweeping the target with a magnetic field.
13. The method of claim 12 wherein uniformly sweeping the target with a magnetic field includes sweeping a magnet in one direction across the target where the magnet extends beyond the target in the opposite direction.
14. The method of claim 2 wherein the target is an alloyed target.
15. The method of claim 14 wherein the alloyed target includes one or more rare-earth ions.
16. The method of claim 14 wherein the alloyed target includes Si and Al.
17. The method of claim 14 wherein the alloyed target includes one or more elements taken from a set consisting of Si, Al, Er, Yb, Zn, Ga, Ge, P. As, Sn, Sb, Pb, Ag, Au, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy Ho, Tm, and Lu.
18. The method of claim 14 wherein the alloyed target is a tiled target.
19. The method of claim 18 wherein each tile of the tiled target is formed by prealloy atomization and hot isostatic pressing of a powder.
20. The method according to claim 2 , wherein the narrow band-rejection filter has a bandwidth of about 100 kHz.
21. The method according to claim 2 , wherein the RF frequency is about 2 MHz.