Magnetically enhanced low temperature-high density plasma-chemical vapor deposition plasma source for depositing diamond and diamond like films
A magnetically enhanced low temperature high density plasma chemical vapor deposition (LT-HDP-CVD) source has a hollow cathode target and an anode, which form a gap. A cathode target magnet assembly forms magnetic field lines substantially perpendicular to the cathode surface. A gap magnet assembly forms a magnetic field in the gap that is coupled with the cathode target magnetic field. The magnetic field lines cross the pole piece electrode positioned in the gap. The pole piece is isolated from ground and can be connected to a voltage power supply. The pole piece can have negative, positive, floating, or RF electrical potentials. By controlling the duration, value, and sign of the electric potential on the pole piece, plasma ionization can be controlled. Feed gas flows through the gap between the hollow cathode and anode. The cathode can be connected to a pulse power or RF power supply, or cathode can be connected to both power supplies. The cathode target and substrate can be inductively grounded.
1. A magnetically enhanced plasma-chemical vapor deposition (LT-HDP-CVD) apparatus comprising:
a hollow cathode assembly;
an anode positioned on top of the hollow cathode assembly, thereby forming a gap between the anode and the hollow cathode assembly;
a cathode magnet assembly;
a row of magnets that generate a magnetic field in the gap and a magnetic field on a surface of the hollow cathode assembly with the cathode magnet assembly such that magnetic field lines are substantially perpendicular to the hollow cathode assembly;
a power supply that generates a train of negative voltage pulses that generates a pulse electric field in the gap perpendicular to the magnetic field lines, the pulse electric field igniting and sustaining plasma during a pulse, a frequency, duration, and amplitude of the train of negative voltage pulses being selected to increase a degree of dissociation of the feed gas molecules atoms.
2. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 , further comprising a pole piece positioned adjacent to the gap and connected to the power supply.
3. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 further comprising a radio frequency (RF) power supply connected to the hollow cathode assembly, the RF power supply generating output voltage with a frequency is in a range of about 1 MHz to 100 MHz.
4. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 further comprising:
a substrate holder; and
an RF substrate bias power supply connected to the substrate holder.
5. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 4 further comprising an inductor connected between the substrate holder and ground.
6. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 further comprising:
a substrate holder; and
a substrate bias power supply connected to the substrate holder, the substrate bias power supply generating a bias voltage on the substrate in a range of about −10 V to −2000 V.
7. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 , wherein the magnetic field in the gap is in a range of about 50 G to 5000 G.
8. The magnetically enhanced LT-HDP-CVD apparatus, as defined by claim 1 wherein the cathode magnet assembly is rotatable.
9. A method of magnetically enhanced plasma-chemical vapor deposition (LT-HDP-CVD) comprising:
providing a hollow cathode;
forming a gap between the hollow cathode and an anode;
positioning a cathode magnet assembly;
generating a magnetic field in the gap such that magnetic field lines are substantially perpendicular to a surface of the hollow cathode;
positioning a pole piece in the gap;
providing a pulse power to the hollow cathode that ignites and sustains volume discharge; and
generating a train of negative voltage pulses, a frequency, duration, and amplitude of the train of negative voltage pulses being selected to increase a degree of dissociation and ionization of feed gas molecules and atoms.
10. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 , further comprising a power supply connected to the pole piece.
11. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 further comprising:
connecting an RF power supply to the hollow cathode; and
generate output voltage using the RF power supply with a frequency in a range of about 1 MHz and 100 MHz.
12. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 , wherein the power supply generates an output voltage with a value in a range of about −100 V to −3000 V.
13. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 , further comprising connecting a substrate bias power supply to a substrate holder; and
generating bias voltage on the substrate in a range of about −10 V to −2000 V.
14. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 , wherein the magnetic field in the gap is in a range of about 50 G to 10000 G.
15. The method of magnetically enhanced LT-HDP-CVD deposition, as defined by claim 9 , wherein the hollow cathode comprises carbon.