Spectroscopic studies of plasma processing are critical to the development of fundamental models and sensors for exploitation of high-density plasmas in materials processing. Gas phase diagnostics yield a tremendous amount of information regarding the identification and fate of reactive atoms, molecules, and ions in a plasma process. Noninvasive, real-time, in situ spectroscopic techniques can reveal the dynamics of energy flow from the electromagnetic power source into the gas phase, and ultimately to the surface undergoing transformation. For example, Stark and Zeeman splitting in atomic spectra indicate the strength and spatial extent of the electromagnetic fields in a reactive gas and serve to quantify the nature of the coupling of the power source into the process predicted by models. In addition, precise measurements of chemical species spatial distributions by laser-induced fluorescence are used to benchmark electron, ion, and neutral chemistry codes. This work is done in close collaboration with plasma physicists (theory and experimental), surface chemists, and processing experts at NRL. (64.15.15.B2737, “Surface Chemistry of Electronic Materials.”)

The primary apparatus is an inductively coupled power source that operates in either continuous wave or pulse-modulated modes. A radio frequency biased stage capable of accommodating 4” wafers is available and interchangeable with a differentially pumped mass spectrometer for incident and product flux characterization. Laser resources such as Nd³⁺:YAG and excimer pumped dye lasers with the appropriate frequency harmonic conversion modules, and tunable infrared (IR) diode laser spectrometers are available. Fourier-transform IR spectrometers and liquid nitrogen cooled, gateable, charge coupled device detectors with image intensifiers can be used in conjunction with a variety of monochromators for spectral and spatially resolved detection systems. (See also 64.15.15.B2736, “Chemical Vapor Processing.”).

 

key words

Etching; Laser-induced fluorescence; Modeling; Optical emission; Plasma processing; Pulsed plasma; Spectroscopy;

Citizenship:  Open to U.S. citizens and permanent residents

Level:  Open to Postdoctoral applicants