By Andy Choi
Researchers at the Fraunhofer applied research organization in Europe have developed a lateral drift field photodetector (LDPD) for CMOS chips.
High-speed CMOS sensors provide better images
CMOS sensors are being widely used in digital photography. When compared to other sensors they are easier to handle, possess better power consumption and are more economic to manufacture. These qualities have led to their wide adaptation in digital cameras and cell-phones.
Miniaturization in electronics has led to the achievement of pixels as small as 1 µm. Certain low-light applications, including astronomy, X-ray photography and fluorescence require a larger pixel area of over 10 µm. They use pinned photodiodes (PPD) for conversion of light signals into pulses of electricity. PPDs are optoelectronic components, and they play a critical role in image processing. PPDs have a low read-out speed when the sizes of pixels exceed a certain value. And applications working on low light require high image rates.
In the newly developed LDPD optoelectronic component, the carriers of charges move to the readout node at high speed. The researchers have accelerated this diffusion process hundred-fold. They have also made improvements to the conventional 0.35 µm standard-based CMOS chip manufacturing processes. The Fraunhofer researchers have developed a prototype and have also patented the high-speed CMOS image sensor.
These CMOS sensors can also be used as three-dimensional sensors for recording the environment, in applications including crash protection.