Towards infrared depth sensors based on amorphous semiconductors integrable on CMOS

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Optical Sensing

Background:

• Current optical depth sensing technologies face challenges in balancing measurement performance with system simplicity and scalability, especially at high pixel densities.
• Existing solutions often struggle to achieve high precision while maintaining ease of integration and cost-effectiveness.

Purpose of the Study:

• To introduce and evaluate the intrinsic photomixing detector (IPD) as a solution for high-precision time-of-flight depth sensing.
• To demonstrate the IPD's capability to overcome limitations of current depth sensing technologies.
• To explore the potential of IPD for scalable and CMOS-compatible integration.

Main Methods:

• Utilizing an electrical referenced nonlinear mixing process in amorphous semiconductors for depth sensing.
• Developing and testing first depth sensor prototypes based on the IPD technology.
• Evaluating performance at visible (457 nm) and near-infrared (785 nm) wavelengths.

Main Results:

• Achieved mixing efficiencies of up to 47% in the developed prototypes.
• Demonstrated a mean depth resolution of 5 mm at distances from 0 m to 2 m using 457 nm wavelength.
• Confirmed near-infrared detection capabilities with sensitivity down to 450 µW/cm² at 785 nm.

Conclusions:

• The intrinsic photomixing detector (IPD) offers a promising pathway towards high-performance depth sensing.
• IPD enables a simple, scalable, and CMOS-compatible integration platform for depth sensors.
• The technology supports high pixel fill factors up to 100%, paving the way for next-generation optical depth sensing solutions.