Design of Low-Noise High-Gain CMOS Transimpedance Amplifier for Intelligent Sensing of Secondary Electrons

This paper presents a transimpedance amplifier (TIA) which was optimized for detecting very weak signals generated for microscopy imaging in the scanning electron microscope (SEM). This high-performance TIA was designed using a nomograph approach. The TIA was constructed and fabricated in an Austriamicrosystems 0.35-mu m CMOS technology. The circuit, connected to an integrated photodiode with a junction capacitance of 10 pF, exhibited a transimpedance gain of 107.3 dB Omega, a bandwidth of 12.5 MHz, an input-referred noise of 3.54 x 10-12A/root Hz, and an SNR of 8, which manifested that the design is suitable for integration into a multipixel CMOS photon detector to perform intelligent sensing of secondary electrons in the SEM.