Development of an electron diffractometer using an electron-bombarded amplified MOS imager

We developed an electron diffractometer (ED) using an amplified metal-oxide-semiconductor (MOS) imager (AMI) overlaid with electron-bombarded amorphous silicon (a-Si). The gain of ED-AMI is 3500 at 20 kV. The gain is under unity below 2 kV because of the penetration loss of the Al layer. The fixed pattern noise (FPN) is below the detection limit. Although the SN ratio of the conventional instruments is 21.3 dB at 73 nA diffraction current, the SN ratio of ED-AMI becomes 47.3 dB. The SN ratio in this device is 26.0 dB larger than the conventional value, and is suitable for the detection of fast weak structural change such as in an amorphous material.