Measurements
Contents
Materials Characterization
Atomic Force Microscopy (AFM)
CNSI has a room devoted to AFM including 2 models Asylum and NanoScope. Contact Mark Cornish <cornish@engineering.ucsb.edu> to get tips and register. The cleanroom also has a NanoScope AFM managed by Bill Mitchel <mitchell@ece.ucsb.edu>.
Asylum AFM
Media:Asylum_AFM_MFC-3D_Procedure_v2.docx
Media:Asylum_AFM_MFC-3D_Procedure_v1_-_Basic_Tapping_Mode.docx
NanoScope AFM
Bill will approve you to sign-up once someone he trusts trains you.
Analysis
Igor Pro demo: http://www.wavemetrics.com/support/demos.htm Asylum download requires a login, and to get one takes a little while. Is it possible to upload that to the wiki? Gwyddion and GTK+: http://gwyddion.net/download.php#stable-osx it recommends a specific GTK+, not sure why it matters though. If you have it from Pidgin or something I'm sure it'll work.
Focused Ion Beam
Mainly used to create/image cross sections and perform TEM lamina preparations.
Cross Sections
Needs gold coating or conducting surface.
Will mill out a trench with ion beam and image the cross section at a 52 ° tilt. Can get up to 100kX SEM images and normally create trenches up to 20μm
Best when you don't want to destroy your samples and/or your tolerance to cleaving is less than 25 µm, otherwise try cleaving
Contact Daryl Spencer to setup a session, two weeks notice is usually sufficient.
X-Ray Diffraction (XRD)
XRD qualification of wafer:
This is one scan in ~20minutes if you know the offcut and direction already.
- Note offcut amount and direction. Draw arrow relative to wafer flats. ([110] is the direction perpendicular to the major flat)
- ID the layer peak(s), if separated from the substrate peak, and give the strain(s) (or just peak separation)
- ID superlattice/QW fringes. Count them (e.g. -2 to +3) and note spacing in arcseconds
- Make note of any other strong fringe peaks or broad/mysterious layer peaks
NB: Offcut on GaAs may be up to 10degrees. (XRD person try a pole search to locate). InP offcut ~0.2degrees is standard and often not noticed during XRD.
Optical Characterization
LI curves
"Example:" This technique allows you to measure output power vs. injection current. The follwoing equipment is used:
- Keithley (link to equipment)
- Agilent powermeter (link)
The measurement can be controlled using this (link) software. A sample plot looks like this: (insert picture). More about this technique can be found in:
- Mr.X et al., IEEE Journ. of Lightwave Technol., vol. x, pp. xxx-xxx, Aug. 2005
- Our own uploaded description (in doc format maybe)
Electrical characterization
Analysis: http://gwyddion.net/download.php#stable-osx
Microwave measurements
Linearity measurements (OIP2, OIP3, SFDR,...)