A CMOS-Compatible Image Sensor

Opportunity

The proliferation of smart consumer electronic devices, which are integral to our daily lives, has created huge market opportunities. A key feature of these devices is their ability to capture digital images instantly, typically achieved through an integrated complementary metal oxide semiconductor (CMOS) image sensor. This sensor comprises an array of minute optically sensitive electronic elements such as p-n semiconductor junctions or photodiodes. 

This invention introduces a new negative photoconductivity behaviour observed in the soft breakdown of oxide dielectric material under electrical stress. A nanoscale conducting filament forms within the oxide network, with its resistance alternating between high and low states, establishing the foundation for binary memory states. The negative photoconductivity effect enables the integration of optical functionality into memory devices, allowing for light-mediated multi-level memory cells and an image sensor with built-in non-volatile memory capability. 

Technology

This technology features a sensor element for sensing optical light. It includes a first electrode connected to a first supply voltage, a second electrode connected to a second supply voltage, and an oxide dielectric element positioned between the electrodes. When the potential difference between the supply voltages exceeds a threshold, a conductive filament forms in the oxide dielectric element, reducing its resistance. The sensor element also incorporates a detector. The first electrode allows optical light to pass through to the oxide dielectric element and the detector detects an increase in the resistance of the oxide dielectric element upon exposure to optical light. 

Applications & Advantages

Main application areas include fast-switching and low power CMOS imaging sensors. 

Advantages: 

• Enables rapid image capture and processing. 
• Ideal for energy-efficient devices. 
• Integrates memory and imaging functions in one device. 
• Incorporates advanced optical features into memory devices.