VASE Ellipsometer

The VASE® is an accurate and versatile ellipsometer for research on all types of materials: semiconductors, dielectrics, polymers, metals, multi-layers, and more. It combines high accuracy and precision with a wide spectral range – 193 to 3200nm. Variable wavelength and angle of incidence allow flexible measurement capabilities, including:
• Reflection and Transmission Ellipsometry
• Generalized Ellipsometry (Anisotropy, Retardance, Birefringence)
• Reflectance (R) and Transmittance (T) intensity
• Cross-polarized R/T
• Depolarization
• Scatterometry
• Mueller-matrix

OVERVIEW

Why a VASE?

Maximum Data Accuracy

The VASE features a rotating analyzer ellipsometer (RAE) combined with our patented AutoRetarder® for unparalleled data accuracy.

High Precision Wavelength Selection

The HS-190™ scanning monochromator is designed specifically for spectroscopic ellipsometry. It optimizes speed, wavelength accuracy and light throughput, while automatically controlling selection of wavelengths and spectral resolution.

Flexible Measurements

The VASE features a vertical sample mount to accommodate a large variety of measurement geometries including reflection, transmission, and scattering.

AutoRetarder® Technology

Rotating Analyzer Ellipsometers (RAE) maximize data accuracy near the “Brewster” condition – where Ψ/Δ data are content-rich. However, this region can be limiting for samples with reduced signal. The patented AutoRetarder is a computer controlled waveplate which modifies the light beam polarization before it reaches the sample. This produces optimum measurement conditions for any sample – under any conditions.

AutoRetarder accurately measures:

• Ψ and Δ over the full range!
• Generalized (anisotropic) Ellipsometry
• Depolarization data
• Mueller-matrix data

APPLICATIONS

Optical Coatings

The AutoRetarder® measures Δ accurately even when close to 0° or 180° which helps characterize thin films on transparent substrates, such as glass or plastics. Applications include decorative coatings, anti-reflection and high-reflection layers and stacks, low-emissivity films, electrochromic and photochromic layers and more.

Laser optics

Accurate wavelength selection using monochromator allows measurements at the operating wavelength for optics, e.g. 1550nm, 1310nm, 980nm, 632.8nm, 589nm …

Thin Films

VASE is sensitive to layer thickness down to sub-nanometer. For absorbing layers, the VASE allows measurement of SE and Transmission Intensity (T). When analyzed simultaneously, SE + T often allow determination of n, k, and t. For example, this thin metal layer is only 14 nm thick.

SE + T for thin metal layer.

SE + T for thin metal layer.

Semiconductors

Bandgap, electronic transitions and critical points can be measured for semiconductor materials such as GaN, InP, SiGe, CdTe, etc. Good wavelength resolution and ability to measure depolarization insure accurate optical constants.

SiGe optical constants with varying composition.

Photosensitive Materials

The monochromator is positioned before the sample, so only low intensity monochromatic light strikes the sample. This prevents exposure of photosensitive samples.

Optical constants of a photolithography film.

Models

Base Model VASE

vase-ellipsometer-profile Standard Spectral Range: 240-1700 nm
• Vertical sample stage with vacuum mount can accommodate up to 200 mm diameter samples (call for custom sample mounting)
• Automated angle of incidence from 15° to 90°
• Double-chamber monochromator for superior stray-light rejection
• AutoRetarder: patented technology provides highest accuracy on any sample.
• Also measure depolarization, anisotropy, and Mueller-matrix data.

Spectral Range Upgrade

DUV 193-240nm
XNIR extension to 2500nm
XXIR extension to 3200nm
PMT Detector Add an auxiliary PMT detector for improved S/N performance in the UV.
(Only used for wavelengths below 300nm)
SPECIFICATIONS
Ellipsometer Configuration RAE with AutoRetarder
Wavelength Range Standard (Double Chamber)
VASE+DUV
VASE+DUV+XNIR
VASE+DUV+XXIR
VASE+XNIR
VASE+XXIR
240-1700 nm
193-1700 nm
193-2500 nm
193-3200 nm
240-2500 nm
240-3200 nm
Number of Wavelengths User defined before measurement
Angles of Incidence 15°-90°
Data Acquisition Rate 0.1 to 3 seconds per wavelength
Max substrate thickness 20mm

Facility Requirements

Power 100, 110, 220, 240 VAC, 50-60Hz, 4/8 Amps

Table to be supplied by end user.

Dimensions

vase-ellipsometer-dimensions

ACCESSORIES

Camera

vase-ellipsometer-camera Add camera with display to view spot location on sample. The light beam may not appear on smooth, specular surfaces.

Commonly sold with Standard or Alternate Focusing

Automated Translation (150x150mm)

vase-ellipsometer-150x150mm-automated-translation Translator Size: 150×150 mm XY

Standard stage and Translation stage are swappable.

Automated Translation (50x50mm)

vase-ellipsometer-50x50mm-automated-translation Translator Size: 50×50 mm XY

Includes two exchangeable stages.

Open stage with hole for transmission mapping (41×41 mm)

Standard stage and Translation stage are swappable.

Commonly sold with Alternate Focusing

Standard Focusing

vase-ellipsometer-standard-focusing-probes 100 or 200 μm beam diameter depending on installed optical fiber.

Commonly sold with Camera

Alternate Focusing

vase-ellipsometer-alternate-focusing-probes 200 or 400 μm beam diameter depending on installed optical fiber.

Commonly sold with Camera and 50×50 mm Automated Translation.

Cryostat

vase-ellipsometer-vertical-cryostat Temperature range: 4.2 to 500 Kelvin OR 4.2 to 800 Kelvin

Angle: 70°

Includes UHV chamber/cryostat, turbo pump,and temperature controller.

Cryostat can be installed and removed, which allows the user to switch between the standard sample stage and the cryostat.

Wide-Range Temperature Stage

linkam-ellipsometer-heatcell-horizontal Temperature range: -70°C to 600°C

Angle: 70°

Active Cooling with Liquid Nitrogen

Sample area 22mm in diameter

Standard Heat Stage (HTC-100)

htc-100-heatcell-vertical-stage

Temperature range: Room Temp to 300°C

Angle: 70°

Passive Cooling

Sample area up to 50mm diameter

Rotation Stage

vertical-ellipsometer-rotation-stage

Automated high precision sample rotation (360° Theta-only) stage.

Useful when studying anisotropy. Through-hole behind sample allows transmitted beam measurements from normal incidence (0°) to ±19°.

Standard stage and rotation stage are swappable.

Manual Sample Translation

50-50mm-manual-vertical-translation-stage

Translator Size: 50×50 mm XY

Standard stage and Manual Sample Translation stage are swappable.

Liquid Prism Cell

vase-ellipsometer-liquid-prism-cell

The liquid minimum deviation cell is used to determine liquid refractive index (n and k) using a hollow prism cell.  Measure minimum deviation angles through the liquid filled prism.  Two cells are included:

  • 6 mL (60° angle of incidence)
  • 5 mL (30° angle of incidence)

Features Automated Z-Translation

37mL Electrochemical Cell

37mL-vertical-ellipsometer-electrochemical-cell

General purpose liquid cell with vertical mount above liquid line for convenient electrochemical work.

5mL Vertical Liquid Cell

5mL-vertical-ellipsometer-liquid-cell

General purpose liquid cell with 5mL volume.

270µL Vertical Liquid Cell

270uL-vertical-ellipsometer-liquid-cell

Ultra low-volume liquid cell. (Minimum sample size 8 mm x 21 mm)