Project Title:

Photoetched Echelle Gratings in Silicon

08.18-9450
NAS5-30844
Photoetched Echelle Gratings in Silicon
EIC Laboratories, Inc.
	111 Downey Street
	Norwood, MA 02062
		Michael M. Carrabba
(617-769-9450)

Abstract:

	Echelle diffraction gratings are critical components for spectral analysis of light
from stellar and albedo sources. Photo-electrochemical etching (PEC) is a process
for producing diffraction gratings directly into semiconducting materials with a
high degree of control of reaction rate, lateral uniformity, and groove angle. Phase
I will determine the feasibility of making Echelle diffraction gratings in silicon
by the PEC method. Silicon possesses the crystallographic properties that would allow
direct PEC fabrication of deep, low-pitch, Echelle gratings. Silicon gratings greater
than 3" x 3" in size are possible since high-quality and large area (>6" diameter)
crystals are available. In Phase I, the effects of photo-etchant composition, exposure
times, light intensity, masking procedure, and doping density of the Si will be examined.
The goal of the project is the production of practical-size Echelle gratings for
evaluation by NASA.

Potential Commercial Application:

Potential Commercial Applications: The gratings would be useful for free-electron
lasers and synchrotron light sources and as masters for gratings used in high-resolution,
commercial spectrographs. PEC techniques could be used to fabricate solid-state electronic
devices, micro-mechanical structures, and sub-millimeter optical filters.