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A matchless plasma source is described. The matchless plasma source includes a controller that is coupled to a direct current (DC) voltage source of an agile DC rail to control a shape of an amplified square waveform that is generated at an output of a half-bridge transistor circuit. The matchless p

A matchless plasma source is described. The matchless plasma source includes a controller that is coupled to a direct current (DC) voltage source of an agile DC rail to control a shape of an amplified square waveform that is generated at an output of a half-bridge transistor circuit. The matchless plasma source further includes the half-bridge transistor circuit used to generate the amplified square waveform to power an electrode, such as an antenna, of a plasma chamber. The matchless plasma source also includes a reactive circuit between the half-bridge transistor circuit and the electrode. The reactive circuit has a high-quality factor to negate a reactance of the electrode. There is no radio frequency (RF) match and an RF cable that couples the matchless plasma source to the electrode.

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1. A matchless plasma source for providing radio frequency (RF) power to an electrode of a plasma chamber used for processing a substrate, comprising: a controller;a signal generator configured to provide an input RF signal at an operating frequency in response to a setting by the controller;a gate

1. A matchless plasma source for providing radio frequency (RF) power to an electrode of a plasma chamber used for processing a substrate, comprising: a controller;a signal generator configured to provide an input RF signal at an operating frequency in response to a setting by the controller;a gate driver configured to receive the input RF signal and producing a plurality of square wave signals;an amplification circuit configured to receive the square wave signals from the gate driver and generate an amplified square waveform, the amplification circuit having an agile direct current (DC) rail that is interfaced with the controller,wherein the controller is configured to set voltage values for the agile DC rail to cause the amplified square waveform to be output from the amplification circuit in a shaped envelope defined by a shaping voltage signal; anda reactive circuit configured to extract a shaped sinusoidal waveform from the amplified square waveform, the shaped sinusoidal waveform being output based on the shaped envelope defined by the shaping voltage signal,wherein the reactive circuit is configured to provide the RF power of the shaped sinusoidal waveform to the electrode for generating a plasma for said processing of the substrate. 2. The matchless plasma source of claim 1, wherein each of the square wave signals received from the gate driver is a pulsed waveform that pulses at the operating frequency between a low level and a high level. 3. The matchless plasma source of claim 1, wherein the amplification circuit is a half-bridge transistor circuit or full bridge H circuit, wherein the electrode is an antenna. 4. The matchless plasma source of claim 3, wherein the half-bridge transistor circuit includes a plurality of field-effect transistors or a plurality of insulated-gate bipolar transistors. 5. The matchless plasma source of claim 4, wherein the field-effect transistors are cooled by a cooling plate. 6. The matchless plasma source of claim 4, wherein the field-effect transistors are arranged in a push-pull configuration, wherein in the push-pull configuration, a first one of the field-effect transistors is on when a second one of the field-effect transistors is off and the second field-effect transistor is on when the first field-effect transistor is off. 7. The matchless plasma source of claim 4, wherein the field-effect transistors have a resistance that allows an instant turning off and turning on of each of the field-effect transistors to reduce delays in the turning on and the turning off. 8. The matchless plasma source of claim 7, wherein one of the field-effect transistors is turned on during a time period in which another one of the field-effect transistors is turned off, wherein the other one of the field-effect transistors is turned on during a time period in which the one of the field-effect transistors is turned off. 9. The matchless plasma source of claim 4, wherein the field-effect transistors are fabricated from at least one of silicon carbide and gallium nitride. 10. The matchless plasma source of claim 1, wherein the amplification circuit includes a tree of transistors, wherein the tree is sized to achieve a desired power level. 11. The matchless plasma source of claim 1, wherein the agile DC rail has a DC voltage source, wherein the amplification circuit includes a half-bridge transistor circuit having a plurality of field-effect transistors, wherein the agile DC rail is coupled to source terminals or drain terminals of the plurality of field-effect transistors depending on whether the field-effect transistors are p-type or n-type. 12. The matchless plasma source of claim 1, wherein the agile DC rail has a DC voltage source that is configured to generate the shaping voltage signal having the voltage values to shape the amplified square waveform according to the shaping voltage signal. 13. The matchless plasma source of claim 1, wherein the amplified square waveform is shaped to have the shaped envelope. 14. The matchless plasma source of claim 1, wherein the shaped envelope is a multi-state pulse-shaped envelope, or a triangular-shaped envelope, or a continuous-shaped envelope, or an arbitrary-shaped envelope. 15. The matchless plasma source of claim 1, wherein the reactive circuit has a reactance that is configured to reduce a reactance of the electrode, or a reactance of the plasma when formed within the plasma chamber, or a reactance of a connection that couples the reactive circuit to the electrode, or a combination thereof. 16. The matchless plasma source of claim 1, wherein the reactive circuit has a quality factor to remove higher-order harmonics of the amplified square waveform to generate a fundamental waveform, wherein the shaped sinusoidal waveform is the fundamental waveform having the shaped envelope. 17. The matchless plasma source of claim 1, wherein a connection between the reactive circuit and the electrode lacks an RF cable and an RF match. 18. The matchless plasma source of claim 1, further comprising a voltage and current probe configured to measure a complex voltage and a complex current at an output of the amplification circuit, and a phase difference between the complex voltage and complex current, wherein the controller is configured to control the operating frequency of the signal generator to reduce the phase difference to control the RF power of the shaped sinusoidal waveform. 19. The matchless plasma source of claim 18, wherein the agile DC rail includes a DC voltage source, wherein the controller is configured to control the DC voltage source to control a voltage of the shaped sinusoidal waveform, or a current of the shaped sinusoidal waveform, or the RF power of the shaped sinusoidal waveform. 20. The matchless plasma source of claim 1, further comprising: a voltage probe configured to measure a complex voltage at an output of the amplification circuit;a current probe configured to measure a complex current on a connection between the reactive circuit and the electrode,wherein the controller is configured to calculate a phase difference between the complex voltage and the complex current, wherein the controller is configured to control the operating frequency of the signal generator to reduce the phase difference to control the RF power of the shaped sinusoidal waveform. 21. The matchless plasma source of claim 20, wherein agile DC rail includes a DC voltage source, wherein the controller is configured to control the DC voltage source to control a voltage of the shaped sinusoidal waveform, or a current of the shaped sinusoidal waveform, or the RF power of the shaped sinusoidal waveform. 22. The matchless plasma source of claim 1, further comprising an arbitrary waveform generator configured to generate a shaping control signal to facilitate generation of the shaped envelope of an arbitrary shape based on the voltage values, wherein the shaping control signal shapes the amplified square waveform according to the shaped envelope. 23. The matchless plasma source of claim 22, wherein the arbitrary shape has multiple slopes of the shaped envelope, wherein the slopes change from one state to another in a controlled manner that is determined by the controller. 24. The matchless plasma source of claim 1, wherein the reactive circuit has a reactance that is adjustable by adjusting a capacitance, or an inductance, or a combination thereof of the reactive circuit. 25. A method for providing radio frequency (RF) power to an electrode of a plasma chamber used for processing a substrate, comprising: generating, by a signal generator, an input RF signal at an operating frequency in response to a setting received from a controller;producing, by a gate driver, a plurality of square wave signals upon receiving the input RF signal from the signal generator;generating, by an amplification circuit, an amplified square waveform upon receiving the square wave signals from the gate driver and generating an amplified square waveform, the amplification circuit having an agile direct current (DC) rail that is interfaced with the controller,instructing, by the controller, to set voltage values for the agile DC rail to cause the amplified square waveform to be output from the amplification circuit in a shaped envelope defined by a shaping voltage signal;extracting, by a reactive circuit, a shaped sinusoidal waveform from the amplified square waveform, the shaped sinusoidal waveform being output based on the shaped envelope defined by the shaping voltage signal; andsending, to the electrode via a connection between an output of the reactive circuit and the electrode, the shaped sinusoidal waveform for generating a plasma for said processing of the substrate. 26. The method of claim 25, wherein each of the square wave signals is a pulsed waveform that pulses at the operating frequency between a low level and a high level. 27. The method of claim 25, wherein the amplification circuit includes a plurality of field-effect transistors that are arranged in a push-pull configuration, the method further comprising: turning a first one of the field-transistors on when a second one of the field-effect transistor is off; andturning on the second field-effect transistor when the first field-effect transistor is off. 28. The method of claim 27, wherein the field-effect transistors are fabricated from silicon carbide to define silicon carbide field-effect transistors having a resistance that allows said turning off and turning on of each of the field-effect transistors to be substantially instantaneous to reduce delays in the turning on and the turning off. 29. The method of claim 28, wherein the field-effect transistors are substantially instantaneously turned on and turned off in less than a pre-determined time period. 30. The method of claim 25, further comprising achieving, by a tree of transistors of the amplification circuit, a desired power level. 31. The method of claim 25, further comprising generating, by a DC voltage source of the agile DC rail, the shaping voltage signal according to the voltage values to shape the amplified square waveform. 32. The method of claim 25, wherein the amplified square waveform is shaped to have the shaped envelope. 33. The method of claim 25, wherein the shaped envelope is a multi-state pulse-shaped envelope, or a triangular-shape envelope, or a continuous-shaped envelope, or an arbitrary-shaped envelope. 34. The method of claim 25, further comprising reducing, by a reactance of the reactive circuit, a reactance of the electrode, or a reactance of the plasma when formed within the plasma chamber, or a reactance of the connection that couples the reactive circuit to the electrode, or a combination thereof. 35. The method of claim 25, further comprising removing, by a quality factor of the reactive circuit, higher-order harmonics of the amplified square waveform to generate a fundamental waveform, wherein the shaped sinusoidal waveform is the fundamental waveform having the shaped envelope. 36. The method of claim 25, wherein communication between the reactive circuit and the electrode is achieved without an RF cable and an RF match. 37. The method of claim 25, further comprising: measuring, by a voltage and current probe, a complex voltage at an output of the amplification circuit, a complex current at the output of the amplification circuit, and a phase difference between the complex voltage and complex current; andcontrolling the operating frequency of the signal generator to reduce the phase difference to control the RF power of the shaped sinusoidal waveform. 38. The method of claim 37, further comprising controlling a DC voltage source of the DC agile rail to control a voltage of the shaped sinusoidal waveform, or a current of the shaped sinusoidal waveform, or the RF power of the shaped sinusoidal waveform. 39. The method of claim 25, further comprising: measuring, by a voltage probe, a complex voltage at an output of the amplification circuit;measuring, by a current probe, a complex current;calculating a phase difference between the complex voltage and the complex current; andcontrolling the operating frequency of the signal generator to reduce the phase difference to control the RF power of the shaped sinusoidal waveform. 40. The method of claim 39, further comprising controlling, a DC voltage source of the agile DC rail, to control a voltage of the shaped sinusoidal waveform, or a current of the shaped sinusoidal waveform, or the RF power of the shaped sinusoidal waveform. 41. The method of claim 25, further comprising, generating the shaped envelope of an arbitrary shape based on the voltage values for shaping the amplified square waveform according to the shaped envelope. 42. The method of claim 41, wherein the arbitrary shape has multiple slopes of the shaped envelope, wherein the slopes change from one state to another in a controlled manner that is determined by the controller. 43. The method of claim 25, further comprising adjusting a reactance of the reactive circuit by adjusting a capacitance, or an inductance, or a combination thereof of the reactive circuit. 44. A matchless plasma source comprising: an input section;an output section coupled to the input section;a reactive circuit coupled to the output section and coupled via a connection to an electrode of a plasma chamber,wherein the input section includes: a controller board;a gate driver coupled to the controller board;wherein the output section includes: a half-bridge transistor circuit coupled to the gate driver, wherein the half-bridge transistor circuit includes a direct current (DC) rail, wherein the DC rail includes a DC voltage source, wherein the controller board is configured to control the DC voltage source to change an envelope of an amplified square waveform at an output of the half-bridge transistor circuit,wherein the reactive circuit is configured to reduce higher-order harmonics of the amplified square waveform to produce a shaped sinusoidal waveform at an output of the reactive circuit,wherein the electrode is an antenna, wherein the controller board includes a controller, wherein the controller board further includes a signal generator coupled to the controller and the gate driver;a voltage and current probe coupled to the output of the half-bridge transistor circuit and to the controller board,wherein the voltage and current probe is configured to measure a complex voltage at the output of the half-bridge transistor circuit, a complex current at the output of the half-bridge transistor circuit, and a phase difference between the complex voltage and complex current, wherein the controller is configured to control an operating frequency of the signal generator to reduce the phase difference to control power of the shaped sinusoidal waveform. 45. The matchless plasma source of claim 44, wherein the controller is configured to control the DC voltage source to control a voltage of the shaped sinusoidal waveform, or a current of the shaped sinusoidal waveform, or the power of the shaped sinusoidal waveform. 46. The matchless plasma source of claim 44, wherein the connection lacks a radio frequency (RF) cable and an RF match between the reactive circuit and the electrode.