Time-Varying Body Instability and Low-Frequency Noise Characteristics of Mini-Field-Dual-Body Silicon-on-Insulator Structure for Analog-Digital Mixed-Mode Circuits

A new silicon-on-insulator (SOI) structure for analog-digital mixed applications was proposed where analog and digital metal oxide semiconductor field effect transistors (MOSFETs) are independently optimized. Two types of field oxide are introduced such that the body bias of analog devices can be effectively controlled whereas the channel region for digital devices is fully depleted without the increase of source/drain resistance. The AC body potential instability was investigated by measurements and modeling of the body-related device characteristics. In addition, low-frequency noise characteristics of analog MOSFETs with different body contact structures are shown and analyzed. It was shown that the proposed structure is a strong candidate for the future SOI technology applicable to analog-digital mixed-mode circuits.