Laboratory Facilities
A Three-Axis Automated
Scatterometer (TAAS) facility has been developed for measuring
BRDF/BTDF of semiconductor wafers and other thin-film materials.
The goniometric table is composed of three rotary stages with
high angular resolution (0.005 degree) and repeatability (0.0006
degree). A lock-in amplifier or a mechanical chopper combined
with transimpedance pre-amplifiers of a large dynamic range can
avoid the background radiation. The sample holder allows a large
sample up to 300 mm diameter to be measured. A heated sample
holder can be included in the system for measurements at the
elevated temperature.
Optic-fiber-coupled laser system
connected with thermoelectric cooler provides excellent
wavelength and power stability within 0.2% fluctuation. The
lasers can be conveniently interchanged for measurements at
different wavelengths. A polarizer selects the polarization of
incident beam, and two divided beams by a beamsplitter go to the
reference detector or the sample.
A monochromator has recently been
purchased and installed for broadband measurements in the
visible and near infrared (0.4 – 2.4
mm
wavelengths). The rotation of two gratings inside the
monochromator and the change of filters allow wavelength
selection from incoherent light source (tungsten lamp) with 0.5
nm accuracy and 0.11 nm precision. An integrating sphere allows the
directional-hemispherical reflectance to be measured in the
visible and near infrared regions. The 8 inch diameter sphere is
coated with PTFE (polytetrafluoroethylene).
An ABB Bomem MB154S
Fourier-transform infrared (FTIR) spectrometer is available for
transmittance and reflectance measurements in the wavelength
region from 0.72 to 20
mm
(14,000 – 500 cm–1). The FTIR is equipped with purge
inlets, a ceramic globar source, and a pyroeletric detector. The
f -number of the output beam to the sample is five,
yielding a half-cone angle of 6 deg, and the opening of the
sample holder is 6 mm in diameter. The reflectance measurements
can be performed with the 10 degree specular reflectance
accessory.
A
high-temperature blackbody calibration source Mikron M360 is
also available in the PI’s lab for calibration of radiation
thermometers and emissivity measurements. Its temperature range
is from 100 to 1100
°C
and accuracy is ±0.2% of reading ±1
°C.
The resolution and the stability is ± 0.1
°C
below 1000
°C.
Atomic Force Microscope. A Digital
Instruments MultiMode Scanning Probe Microscope (SPM), operated
by RHK Technology SPM 1000 Controller and AIM-MI Interface
Module.
High-speed, high
resolution infrared camera. A Santa Barbara Focal Plane (Goleta,
CA) model SBF161 infrared camera, and a custom designed optical
setup to achieve magnifications ranging from 0.4x to 6.5x. The
camera sensor has a 128x128 pixel resolution, 14-bit dynamic
range, can acquire full-resolution images at 1.6 kHz, and is
capable of sampling rates of up to 9.4 kHz at reduced
resolution. At 6.5x magnification (using a germanium compound
lens with broadband antireflection coating to provide
transmission from 2 -12 µm), the spatial resolution is
approximately 7 µm, at the diffraction limit for infrared
optics.
Other resources
The
Microfabrication Facilities in the Woodruff School and
the
Georgia Tech Microelectronics Research Center (MiRC),
including a combination of class 10 to class 1000 laboratories,
are readily accessible for micromachining and surface
characterization.
The
MiRC contains approximately 7,000 sq. ft. of clean room for
advanced device, microstructure, and circuit development. Major
pieces of equipment include: sputtering, thermal and E-Beam
evaporators for thin-film deposition, mask aligners, dicing
saws, scribers, etchers, spinners, furnaces, ellipsometer,
profilometers, SEM, AFM, and precision polishing and lapping
machines. The MiRC building also contains various
workstation-based computer-aided design facilities, a
fully-equipped mask-making facility with a Mann 4800 DSW
configured for direct step on photoplates, and fully equipped
simulation and modeling facilities.
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