Development of high spatial resolution Auger microscope as applied to semiconductor analysis

An Auger microscope equipped with aZrO/WSchottky field emitter was developed. For Auger analysis, spatial resolution under a probe current of more than 1 nA is important. Under such conditions, the aberration by the condenser lens is not negligible. To reduce it, the distance from the emitter to the principal plane of the first condenser lens is reduced by forming its magnetic field overlapping with the accelerating field of the electron. As a result, a spherical aberration coefficient of 10 mm (accelerating voltage 30 kV) was achieved and the spatial resolution was about 10 nm with a probe current of 10 nA and an accelerating voltage of 25 kV. The newly developed Auger microscope combined with the probe tracking system has enabled an Auger image to be obtained, in which a 40 nm gate oxide layer in a cross-sectioned integrated circuit device is clearly observed.