Apparatus and method for sputtering hard coatings

Abstract

A plasma generator includes a chamber for confining a feed gas. An anode is positioned inside the chamber. A cathode assembly is positioned adjacent to the anode inside the chamber. A pulsed power supply comprising at least two solid state switches and having an output that is electrically connected between the anode and the cathode assembly generates voltage micropulses. A pulse width and a duty cycle of the voltage micropulses are generated using a voltage waveform comprising voltage oscillation having amplitudes and frequencies that generate a strongly ionized plasma.

What is claimed is: 
     
         1 - 13 . (canceled) 
     
     
         14 . A pulsed arc power supply comprising:
 a voltage source that generates a voltage at an output;   an energy storage device that is electrically connected to the voltage source, the voltage source charging the energy storage device to store an energy;   a switching device that is electrically connected to energy storage device, the switching device releasing the energy stored in the energy storage device when activated in the form of micro pulses;   a transformer comprising a primary coil that is electrically coupled to the switching device and a secondary coil, the primary coil receiving the energy stored in the energy storage device when the switch is activated and transforming the received energy to the secondary coil in order to generate voltage oscillation where the micro pulses correspond to the voltage oscillation;   a driving circuit that is electrically connected to the diodes, the driving circuit forming the shape of the voltage oscillations; and   the voltage oscillations generate and sustain arc discharge on the cathode.   
     
     
         15 . The pulsed arc power supply of  claim 14 , including arc control circuit including an arc detection means that detects the onset of an arc discharge. 
     
     
         16 . The pulsed arc power supply of  claim 15 , wherein the arc detection means sends a signal to a control device that deactivates drivers for the switching device for a period of time, thereby reducing the voltage between an anode and a cathode assembly to levels that cannot support an arc discharge and therefore generate pulse arc discharge. 
     
     
         17 . The pulsed arc power supply of  claim 14 , wherein the switching device comprises a solid state switching device. 
     
     
         18 . The pulsed arc power supply of  claim 14 , wherein the switching device comprises an insulated gate bipolar transistor device. 
     
     
         19 . The pulsed arc power supply of  claim 14 , wherein at least some of the voltage pulses have predetermined shapes. 
     
     
         20 . The pulsed arc power supply of  claim 14 , wherein at least some of the voltage pulses comprise a low-power stage and a high-power stage. 
     
     
         21 . The pulsed arc power supply of  claim 20  wherein the low power stage includes a first peak voltage having a magnitude and a rise time that is sufficient to generate and sustain a weakly-ionized plasma from a feed gas. 
     
     
         22 . The pulsed arc power supply of  claim 14  wherein at least some of the voltage pulses comprise a low-power stage, a transient stage, and a high-power stage. 
     
     
         23 . The pulsed arc power supply of  claim 22 , wherein the transient stage includes a peak voltage having a magnitude and a rise time that is sufficient to shift an electron energy distribution in a weakly-ionized plasma to higher energies that increase an ionization rate which results in a rapid increase in electron density and a formation of a strongly-ionized plasma. 
     
     
         24 . The pulsed arc power supply of  claim 14 , wherein at least some of the voltage pulses include low frequency voltage oscillations. 
     
     
         25 . The pulsed arc power supply of  claim 24 , wherein an amplitude of the low frequency voltage oscillations is greater than or equal to 50 Volts. 
     
     
         26 . The pulsed arc power supply of  claim 14 , wherein a driving circuit comprises cables what connects pulsed arc source and a cathode. 
     
     
         27 . The pulsed arc power supply of  claim 14 , wherein the driving circuit is electrically connected to the secondary coil. 
     
     
         28 . The pulsed arc power supply of  claim 14 , wherein voltage micro pulses are in the range of 2 microsecond to 100 microseconds. 
     
     
         29 . A method of generating arc plasmas comprising:
 generating a voltage with a voltage source;   the voltage source charging an energy storage device to store an energy, the energy storage device being electrically connected to the voltage source;   a switching device releasing the energy stored in the energy storage device when activated in the form of micro pulses, the switching device being electrically connected to energy storage device;   a transformer comprising a primary coil electrically coupled to the switching device and receiving the energy stored in the energy storage device when the switch is activated and transforming the received energy to a transformer secondary coil in order to generate voltage oscillation where the micro pulses correspond to the voltage oscillation;   a driving circuit forming the shape of the voltage oscillations, the driving circuit being electrically connected between the diodes and the cathode; and   the voltage oscillations generating an arc discharge on the cathode.