Photo-Emission Microscopy using an SiGe detector for NearField resolution
Publication Date: 2014-May-19
The IP.com Prior Art Database
Disclosed is a method for photon detection using a sub-Micron Silicon Germanium (SiGe) P-type/Intrinsic/N-type (P-I-N) Avalanche Photo-Diode (APD) attached to an Atomic Force Microscope (AFM) probe.
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-Emission Microscopy using an SiGe detector for NearField resolution
Emission Microscopy using an SiGe detector for NearField resolution
Current viable Failure Analysis (FA) fault isolation techniques are limited to approximately 1.0uM lateral resolution. Transmission Electron Microscopy (TEM) physical characterization limits sample thickness to less than approximately 0.2uM thickness. This results in the possibility that the TEM sample preparation may miss the defect.
To address this, current practice is to pass multiple samples through the FA process to obtain TEM characterization of a defect. This is a "brute force" approach and is expensive in time, resources, and overall cost.
The novel solution is to use Near-Field Scanning Optical Microscopy (NSOM) equipment, multiple Atomic Force Microscopy (AFM) probes, and a high quality photon detector and electronics to obtain <0.1uM lateral resolution Photon Emission Microscopy (PEM). Mounting a sub-wavelength (25-100nM wide) Avalanche Photo-Diode (APD) on one of the AFM probe tips results in lower detector injection losses and higher signal-to-noise ratios, greatly increasing detectivity. This approach provides adequate defect localization for accurate TEM sample preparation placement.
NOTE: The term "Photon" refers to Evanescent Waves in the optical near-field and may include Surface Plasmon Polaritons.
To implement the solution, two possible electrical probe configurations can be used:
• Atomic Force Microscope (AFM) probing: two or more AFM probes are employed to directly apply electrical power to the Device Under Test (DUT). Probes are simultaneously scanned and placed in an industry standard manner using the tuning fork feedback constant probe height method.
• Focused Ion-beam Microscopy (FIB) contacts to facilitate probing: Focused Ion Beam patterned metal deposition is employed to fabricate low profile, high conductivity contacts to the DUT. Either AFM probes or standard optical microscope probes can be employed to contact the FIB deposited metal and provide electrical stimulus.
Photon detection is accompli...