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NIST SYSTEM CALIBRATES EXCIMER LASERS
NIST
researchers have created a system for homogenizing the beam
intensity of excimer lasers. According to NIST, they are the
only laboratory in the world providing such calibrations.
NIST offers power calibrations for excimer lasers operating
at 248nm and 193nm (157nm lasers are expected to be added
within a year).
While each laser emits only one specific wavelength of light,
the intensity of light in a cross section of the beam may
vary substantially. Thus, NIST scientists use a tiny array
of overlapping lenses to mix various parts of the beam together.
This allows the intensity of the more uniform beam to be measured
with half the uncertainty of previous techniques.
Beam uniformity is important for excimer lasers used in applications
such as laser eye surgery and semiconductor lithography.
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TECHNOLOGY OF THE MONTH
This innovation provides a high-frequency oscillator, which
overcomes the common disadvantages for this type of device
such as the complicated and expensive calibration networks
necessary for stabilization. Particularly usable at a frequency
of 1.6 to 3 GHz, the oscillator consists of the following:
1) An oscillator stage having an output and a voltage-controlled
resonator unit disposed in the oscillator stage
2) A buffer stage connected at the output of the oscillator
stage
3) The oscillator stage including an oscillator transistor
4) The resonator unit including an open resonator in the form
of an etched structure with a wavelength shorter than lambda/4
(where lambda is an oscillator wavelength)
5) The resonator unit including a voltage-controlled variable-capacitance
diode, and a resonator terminal connected between the voltage-controlled
variable-capacitance diode of the resonator unit and the oscillator
transistor of the oscillator stage.
Applications include portable, mobile, or stationary communications
systems such as remote control or measuring systems, particularly
at frequencies of 2.4 to 2.5 GHz.
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NEW PROCESS PRODUCES HIGH-QUALITY THIN FILMS AT HIGH RATES
Current fabrication methods for producing high-quality thin
films present significant challenges. For instance, Chemical
vapor deposition (CVD) has high deposition rates, but frequently
requires expensive precursors, uses high temperatures, and
produces unwanted byproducts.
Physical vapor deposition (PVD) is cleaner, but typically
offers lower deposition rates than CVD and has material limitations,
for example oxides cannot be efficiently deposited with PVD
methods.
AMBP Tech Corporation (Amherst, NY) -- with BMDO SBIR funding
-- has developed an alternative, new laser-assisted molecular-beam
deposition (LAMBD). According to AMBP, this method can create
uniform, high-purity thin films from 50 angstroms to 10 microns
with very flat morphologies.
A reactive process that simplifies the production of complex
films such as carbides, nitrides, and metal alloys, LAMBD
produces films that have applications in the microelectronics
industry, including metal-oxide films and silicon-on-insulator
(SOI) devices.
In addition, LAMBD can be used to create buffer layers for
superconducting tape, an emerging technology with many electric
power applications.
Click here
for more information.
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