Abstract: A plasma processing apparatus and method using a predetermined proportion of relative power between a TE.sub.11 mode and a TM.sub.01 mode to produce radial uniformity of the plasma. A microwave coupler transforms microwave energy from a microwave source into approximately equal proportions of TE.sub.11 and TM.sub.01 modes. In one embodiment, the coupler includes a first arm for generating the TE.sub.11 mode and a second arm for generating the TM.sub.01 mode which are then combined in a cylindrical waveguide section having a sufficient inner diameter to support propagation of both modes. Other circuit components are provided to prevent cross-coupling of the TE.sub.11 mode into the TM.sub.01 generating arm, and vice versa. Thus, the relative proportion of power of each mode may be independently controlled. A magnetic field generator may be used in the apparatus to create an electron cyclotron resonance condition within the plasma.

Abstract: A method and apparatus using a frequency tunable laser to generate a beam which passes through a sample cell and onto an optical detector wherein the tunable laser is modulated at a predetermined frequency which has the undesired effect of producing a periodic interference fringe near an absorption induced signal. An additional level of modulation is applied to the laser beam by a triangular waveform having a predetermined peak-to-peak amplitude and frequency. The triangular waveform peak-to-peak amplitude produces a frequency swing of the laser beam so as to generate from the periodic interference fringe, a signal having reduced components near the absorption induced signal. The signal at the optical detector is demodulated by a lock-in amplifier tuned to a predetermined harmonic of the frequency of the triangular waveform.

Abstract: A microwave source is coupled to an electron cyclotron resonance (ECR) system by circularly polarizing the microwave energy from the source in an angular direction with cooperates with the ECR system's magnetic field to produce electron cyclotron resonance, and coupling the circularly polarized microwave energy to the plasma using a quarter wave vacuum window transformer having a dielectric constant which matches the impedance of the circularly polarized microwave energy to the impedance of the plasma. The impedance matching transformer is preferably a vacuum window of the ECR chamber having quarter wave thickness and the appropriate dielectric constant. For high density plasmas in a standard ECR system of 6 cm radius an alumina window 0.98 cm thick procides optimum coupling. The reflected power from the plasma is thereby minimized to provide a dense plasma for the ECR tool while reducing or eliminating the need for manual external tuners for the microwave source.

Abstract: A triode plasma reactor having first, second and third electrodes for forming a plasma in a reaction chamber from a reactant gas includes a phase modulated potential generator for generating time varying potentials on the second and third electrodes which are phase modulated versions of one another. The phase modulated versions may also include a fixed phase shift between them. By time varying the phase angle relative to a set phase shift, a new dimension of time varying control for the reactor may be obtained. Phase modulation at frequencies from audio frequencies to radio frequencies may be provided. Phase modulation may be accomplished digitally or in the analogue domain.