Specific Process Knowledge/Characterization/PL mapper

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PhotoLuminescence Mapper RPM2000

Positioned in the MOCVD room: F-1, Photo: DTU Nanolab internal

Unless otherwise stated, this page is written by DTU Nanolab internal
Photoluminescence mapping is a non-contact, non-destructive technique for mapping out uniformity of alloy composition, material quality and defects in substrates and of III-V epiwafers. The Rapid Photoluminiscence Mapper (RPM) is equipped with 3 lasers for PL measurements and a white-light source to map out thickness and reflectance of eg layers, microcavities and VCSELs.

Map of two bonded silicon wafers. Red areas are voids between the wafers, Made by Jens Hemmingsen @ DTU Nanolab

It can also be used to map out voids after silicon wafer-bonding. This is done using the reflectance mapping and is using the fact that silicon is transparent for wavelengths above ~1000nm. A void will therefor change the reflectance in that wavelength range. See datasheet below (Thanks to Jens Hemmingsen for the data).

The user manual and contact information can be found in LabManager:

PL mapper

Performance	Excitation	~100 mW @ 405 nm (~70mW on sample) ~10 mW @ 532 nm ~10 mW @ 980 nm white light source for thickness and reflectance measurements
	Detection	integrated signal: Si and/or InGaAs detector Spectral scan: Si CCD (up to 1100 nm), InGaAs photodiode array (900-1700 nm)
	Gratings	600 lines/mm (single frame: 60 nm @ 400 nm) 300 lines/mm (single frame: 120 nm @ 900 nm) 150 lines/mm (single frame: 270 nm @ 1550 nm)
	Chuck sizes	2", 3" and 4"
	Resolution	Minimum spatial resolution 100 µm spotsize ~100 µm
	Wavelength accuracy	< +/- 1 nm
Materials	Allowed substrate materials	III-V Silicon
	Forbidden materials	Do not map any wafers that might leave residues in the machine
Software	RPM viewer	Only on the local PC at the system