Charge-coupled device

Lore & Background

The basis for the CCD is the metal–oxide–semiconductor (MOS) structure, with MOS capacitors as the basic building blocks. In the late 1960s, Willard Boyle and George E. Smith at Bell Labs were researching MOS technology for semiconductor bubble memory and realized that an electric charge could be stored on a tiny MOS capacitor and stepped along a series of capacitors. This led to the invention of the charge-coupled device in 1969. The first experimental device, demonstrated in April 1970, was a row of metal squares on oxidized silicon accessed by wire bonds. The first working CCD made with integrated circuit technology was an 8-bit shift register reported in August 1970.

Companies including Fairchild Semiconductor, RCA, and Texas Instruments began development. Fairchild produced the first commercial devices, including a linear 500-element device and a 2D 100×100 pixel device by 1974. The first color CCD image sensor was created by overlaying a color filter array on this Fairchild CCD in 1974. The interline transfer CCD was proposed in 1973 to reduce smear, and the frame-interline-transfer architecture was developed in 1981. Early CCD sensors suffered from shutter lag, resolved by the invention of the pinned photodiode at NEC in 1980, which became incorporated into most CCD devices by 1987.

Reader's Guide

The CCD's significance lies in its ability to convert incoming photons into electron charges at the semiconductor-oxide interface and read out those charges with high fidelity. Although not the only light detection technology, CCD image sensors became dominant in professional, medical, and scientific applications requiring high-quality image data. The large quality advantage CCDs enjoyed early on narrowed over time, and since the late 2010s CMOS sensors have become the dominant technology, largely replacing CCD image sensors. The invention was recognized with the National Academy of Engineering Charles Stark Draper Prize in 2006 and the Nobel Prize for Physics in 2009. Michael Tompsett received the 2010 National Medal of Technology and Innovation and the 2012 IEEE Edison Medal for pioneering contributions to imaging devices including CCD imagers. The CCD's legacy includes its use in the first KH-11 KENNEN reconnaissance satellite (1976) and in Sony's mass-produced camcorders, with a CCD chip placed on the tombstone of Sony leader Kazuo Iwama.

Did You Know?

• The first experimental CCD device was a row of closely spaced metal squares on oxidized silicon, demonstrated in April 1970.
• The pinned photodiode, invented at NEC in 1980, eliminated shutter lag in CCD sensors.
• The first mass-produced consumer CCD video camera was Sony's CCD-G5, released in 1983.
• The first color CCD image sensor was created in 1974 by overlaying a color filter array on a Fairchild 100×100 pixel CCD.