Microscopic Time-Resolved Free Carrier Absorption Measurement System
MTRFCA-355
Microscopic Time-Resolved Free Carrier Absorption Measurement System MTRFCA-355
 
This microscopic time-resolved measurement system uses pulsed laser excitation and time-resolved free carrier absorption (TR-FCA) to evaluate carrier recombination processes in semiconductor materials with high spatial resolution.
A 355 nm pulsed YAG laser (pulse width: 1 ns, repetition rate: 100 Hz) is used as the excitation source to generate excess carriers in the sample. A 405 nm continuous-wave (CW) laser is used as the probe light, and the time-dependent change in transmitted light intensity due to free carrier absorption is measured with a high-speed photodetector. By analyzing the time-dependent change in probe-light transmittance after excitation, carrier lifetimes can be evaluated without contact or damage to the sample.
The spot size of the excitation light can be changed with a variable aperture, and the light is focused precisely onto the sample by the microscope optics. The probe light is focused to approximately 1 μm and overlapped with the excited region, enabling measurement of carrier lifetime distributions with high spatial resolution. By scanning the sample on the stage, carrier lifetime distributions can be evaluated in both the depth and in-plane directions.
This microscopic time-resolved free carrier absorption measurement system is well suited to carrier lifetime evaluation, carrier lifetime distribution measurement, defect evaluation, and crystal quality evaluation of wide-bandgap semiconductor materials, including SiC.

■Features
• Time-resolved optical excitation with a 355 nm pulsed YAG laser
• Time-resolved free carrier absorption (TR-FCA) measurement with a 405 nm CW laser
• High-spatial-resolution measurement with microscope optics
• Non-contact, non-destructive evaluation using the time-dependent change in free carrier absorption
• Measurement of carrier lifetimes and carrier lifetime distributions
• Optimization of the measurement area with a variable excitation spot size
• Ideal for evaluating wide-bandgap semiconductor materials such as SiC

■Specifications
Excitation Wavelength 355 nm
Laser Cleanup Filter (Excitation) Transmission Band 1: Tabs > 80% (355 nm)
Center Wavelength 1: 355 nm
FWHM Bandwidth 1 (nominal): 1.3 nm (typical); 2.5 nm (maximum)
Blocking Band 1: ODabs > 5 (314.8–351.5 nm)
Blocking Band 2: ODabs > 6 (326.6–349.7 nm)
Blocking Band 3: ODabs > 6 (360.3–390.5 nm)
Blocking Band 4: ODabs > 5 (358.6–422.5 nm)
Fundamental and Second-Harmonic Rejection By a pre-dispersion optical system
Laser Power Adjustment Optics Half-wave plate and polarizer optics
Probe Wavelength 405 nm
Laser Cleanup Filter (Probe) Transmission Band 1: Tavg > 90% (400–410 nm)
Center Wavelength 1: 405 nm
FWHM Bandwidth 1 (nominal): 14.5 nm
Blocking Band 1: ODavg > 3 (358–389 nm)
Blocking Band 2: ODavg > 5 (361–384 nm)
Blocking Band 3: ODavg > 5 (428–457 nm)
Blocking Band 4: ODavg > 3 (420–466 nm)
Measurement Spot 3 μm (theoretical optical diameter at 405 nm)
Objective Lens 40×, wavelength range: 325 nm–500 nm
Imaging Lens 1×, wavelength range: 355 nm–1064 nm
Excitation Light Cut Filter Transmission Band 1: Tavg > 93% (359.6–800.8 nm)
Edge Wavelength 1: 357.8 nm
Blocking Band 1: ODabs > 6 (355 nm)
Blocking Band 2: ODavg > 6 (200–355 nm, typical)
Measurement Wavelength Selection Filter Transmission Band 1: Tavg > 87% (400–410 nm)
Center Wavelength 1: 405 nm
Guaranteed Minimum Bandwidth 1: 10 nm
FWHM Bandwidth 1 (nominal): 14.1 nm
Monitor Camera High-sensitivity UV CCD, wavelength range: 200 nm–700 nm
Excitation and Probe Light Cut Filter Transmission Band 1: Tavg > 93% (421.5–900 nm)
Edge Wavelength 1: 418 nm
Blocking Band 1: ODavg > 5 (270–324 nm)
Blocking Band 2: ODabs > 6 (324–410 nm)
High-Resolution XYZ Positioning Stage Minimum resolution: 10 nm
Travel: 20 mm
Repeatability: ±20 nm
Maximum speed: 10 mm/s
Transient Absorption Photodetector Wavelength range: 230 nm–870 nm
Time response: 0.57 ns
Size 1200 mm × 600 mm

*Specifications and appearance are subject to change without notice for product improvement.