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 depositing a film on a substrate, comprising:
providing a process gas between a target and a substrate;
providing an RF bias at a bias frequency to the substrate;
providing pulsed DC power to the target so that a target voltage alternates between positive and negative voltages; and
filtering the pulsed DC power through a narrow band-rejection filter that rejects power in a narrow band around the bias frequency and passes power at frequencies above and below the bias frequency; and
wherein a material related to the target is deposited on the substrate by exposure of the substrate to the plasma;
wherein the RF biased power is a 2 MHz power supply and the bias frequency is 2 MHz;
and further wherein
the narrow band is 100 kHz and the narrow band-rejection filter is a filter that rejects power at 2 MHz and has a 100 kHz bandwidth.
2. The method of claim 1 , wherein the target is a metallic target and the process gas includes one or more of a set consisting of N2, NH3, CO, NO, C02, C2F6, and halide containing gasses.
3. The method of claim 1 , further including holding the temperature of the substrate substantially constant.
4. The method of claim 1 , wherein the process gas includes a mixture of Oxygen and Argon.
5. The method of claim 1 wherein 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.
6. The method of claim 1 , wherein the target is an alloyed target.
7. The method of claim 6 wherein the alloyed target includes one or more rare-earth ions.
8. The method of claim 6 wherein the alloyed target includes Si and Al.
9. The method of claim 6 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.
10. The method of claim 6 wherein the alloyed target is a tiled target.
11. The method of claim 10 wherein each tile of the tiled target is formed by prealloy atomization and hot isostatic pressing of a powder.
12. The method of claim 1 , wherein the film is an oxide film.
13. The method of claim 1 , wherein the film is a nitride film.
14. The method of claim 1 , wherein the process gas is one or more gasses chosen from the group consisting of Ar, N 2 , NH 3 , 0 2 , C 2 F 6 , C0 2 , CO.
15. The method of claim 1 , wherein the film is one of a group consisting of oxides, fluorides, sulfides, nitrides, phosphates, sulfates, carbonates, or semiconductor materials.
16. The method of claim 1 , wherein the target is a metallic target.
17. The method of claim 1 , wherein the target is a conducting target.
18. The method of claim 1 , wherein the target is an intermetallic target.
19. The method of claim 1 , wherein the pulsed DC power is supplied with a reverse time pulse between about 1.3 and 5 μs.
20. The method of claim 19 , wherein applying the RF bias power to the substrate includes supplying up to 1000 W of RF power to the substrate.
21. The method of claim 1 , wherein applying pulsed DC power through the filter includes supplying pulsed DC power at a pulse frequency of between about 40 kHz and about 350 kHz.
22. The method of claim 1 , wherein the film is a dielectric film.