B13-O-03A high sensitivity and high responsivity pin diode detector design for a backscattering electron detection of SEM

A high sensitivity and high responsivity silicon pin design for the detection of backscattering electrons of a scanning electron microscopy is in progress. The design uses a multi-annular configuration which has four working areas. To improve the sensitivity, the new device is equipped with lateral p-n junctions. The depletion layers formed by p-n junction intersect the surface of detector and it can detect low energy electrons. There are guard rings surrounding each of the working area to prevent the signals from other working areas. Besides, Al metal grid was formed on the top of lateral p-n junctions as electrode to lower the series resistance of large area detector. It improved its responsivity This new BSED can have better surface topography contrast due to its high sensitivity to low energy electrons. It also has more excellent resolution because of its low S/N ratio. And the Al grid enhance the responsivity of the detector. The new BSE detector developed here has potential for use in advanced SEM system.