For electric characterizations, a PM5 probe station by Cascade Microtech mounted on a vibration isolated table in a Faraday cage is used. The system offers a high flexibility of applications, ranging from HF to DC measurements. Electric contact is achieved by metal needles attached to 4 probe heads, which can be individually positioned with an accuracy of ~5µm over the substrate/wafer. The up to 5’’ big substrate is fixed on a movable table using a vacuum chuck while the probe heads are positioned on a separate supporting bridge. A built-in optical microscope facilitates the alignment and navigation of the micromechanically controlled needles and the substrate surface. Via the microscope-attached digital camera, a live picture footage of the needle position can be recorded.
The table, the substrate, the probe heads and the optical microscope can be moved separately, yielding a perfect flexibility regarding various different measurement setups.
The installation is connected to a Semiconductor Characterization System (SCS) 4200 by Keithley combined with a Capacity Voltage (CV) Analyser 590 and Capacity Voltage (CV) Meter 595. The well-screened system allows current measurements of up to 10-15 A by means of a plug-in preamplifier.
Each probe head can be electrically regulated separately. In combination with the flexible positioning relative to the substrate, numerous electric setups can be realized (Resistor, Transistor, 4-terminal sensing etc.).