Two High-Precision Proximity Capacitance CMOS Image Sensors with Large Format and High Resolution

Area of Science:

• Electrical Engineering
• Sensor Technology
• Microelectronics

Background:

• Capacitance imaging sensors are crucial for various applications requiring high sensitivity and spatial resolution.
• Existing sensors face limitations in precision, dynamic range, and resolution.

Purpose of the Study:

• To develop and present two novel high-precision CMOS proximity capacitance image sensors.
• To evaluate their capacitance detection precision, dynamic range, and spatial resolution.

Main Methods:

• Fabrication of two CMOS chips: Chip A (12 μm pitch, 1.68 cm² area) and Chip B (2.8 μm pitch, 1.8 M pixels).
• Implementation of a noise-canceling technique for enhanced capacitance detection.
• Utilizing multiple input pulse amplitudes to achieve a wide dynamic range.
• Experimental verification of spatial resolution using modulation transfer function (MTF) analysis.

Main Results:

• Achieved capacitance detection precision below 100 zF at 20V and below 10 zF at 300V.
• Demonstrated a capacitance detection dynamic range of up to 123 dB.
• Confirmed spatial resolution improvements for Chip B through MTF measurements with various line and space patterns.
• Successfully demonstrated capacitance imaging using the fabricated chips.

Conclusions:

• The newly developed CMOS proximity capacitance image sensors exhibit exceptional precision and dynamic range.
• These sensors represent a significant advancement in capacitance imaging technology, offering higher resolution and sensitivity.
• The demonstrated capabilities pave the way for enhanced applications in fields requiring precise capacitance measurements.