A 70- µ m Pitch 8- µ W Self-Biased Charge-Integration Active Pixel for Digital Mammography.

This paper presents a new low-power compact CMOS active pixel circuit specifically optimized for full-field digital mammography. The proposed digital pixel sensor (DPS) architecture includes self-bias capability at ±10% accuracy, up to 15 nA of dark-current autocalibration, built-in test mechanisms, selectable e(-)/h(+) collection, 10-b lossless charge-integration analog-to-digital conversion, more than 1 decade of individual gain tuning for fixed pattern noise cancellation, and a 50-Mb/s digital-only input/output interface. Experimental results for a 70-µm pitch 8-µW DPS cell example are reported in 0.18-µm CMOS 1-polySi 6-metal technology.

Full-wafer fabrication by nanostencil lithography of micro/nanomechanical mass sensors monolithically integrated with CMOS.

Wafer-scale nanostencil lithography (nSL) is used to define several types of silicon mechanical resonators, whose dimensions range from 20 µm down to 200 nm, monolithically integrated with CMOS circuits. We demonstrate the simultaneous patterning by nSL of ∼2000 nanodevices per wafer by post-processing standard CMOS substrates using one single metal evaporation, pattern transfer to silicon and subsequent etch of the sacrificial layer. Resonance frequencies in the MHz range were measured in air and vacuum. As proof-of-concept towards an application as high performance sensors, CMOS integrated nano/micromechanical resonators are successfully implemented as ultra-sensitive areal mass sensors. These devices demonstrate the ability to monitor the deposition of gold layers whose average thickness is smaller than a monolayer. Their areal mass sensitivity is in the range of 10(-11) g cm(-2) Hz(-1), and their thickness resolution corresponds to approximately a thousandth of a monolayer.