CCD(charge-coupled device)

introduction

CCD(charge-coupled device)

One for detecting light silicon, more than film can more sensitive to detect light changes. Is in charge quantity to indicate different state of dynamic shift register, by the clock pulse voltage to produce and control of semiconductor potential traps changes, realization storage and transmission charge information of solid state electronics device. English abbreviation as CCD. Charge-coupled device by American bell LABS W.S. boyer's hucknall and G.E. Smith in 1969 invention, it consists of a set of rules arrangement of metal oxide semiconductor - - MOS capacitor arrays and input and output circuit composed. The traditional solid-state electronics device, the information of the existence and means, usually use current or voltage. While in CCD, is in charge of information, so CCD expression, with higher sensitivity. Solid imaging, information processing and mass storage is the three main purposes. CCD Various linear array, face array sensor have been successfully used in astronomy, remote sensing, fax, camera, etc. CCD signal processing both digital and analog two kinds of signal processing technology strengths, in medium precision of the radar and communication system widely applied. CCD also can be used as the large capacity serial storage, its access time and system capacity and manufacturing cost between semiconductor memory and disk, drum, memory between.

principle

By the clock pulse voltage to produce and control of semiconductor potential traps changes, realization storage and transmission charge information of solid state electronics device. Actually charge-coupled device (CCD) is a kind of charge quantity to indicate different state of dynamic shift register. In 1969, the American bell LABS W.S. boyer's hucknall and G.E. Smith in exploring PaoQi pieces of magnetic electric simulation process, produce a charge-coupled device principle ideas, and in the experiment verified. They suggest that closely arranged in semiconductor insulation on the surface of the capacitor, can be used to store and transfer charge. At the early stage of the CCD storage and transfer signals charge potential traps are located in silicon - silica interface between, the so-called surface in gully CCD. In 1972 d. kang first conceived majority carrier CCD form, and based on this, people developed body in gully CCD and "peristalsis" type CCD new structure, effectively improve the CCD performance. 1973 American XianTong company made CCD camera sensors, CCD flowed from the lab industrial production practical stage.

The prototype of the CCD in n-type si substrate or P type grow on a layer of silicon dioxide thin layer, again in silica layer deposition and lithography corrosion out metal electrodes, these rules arrangement of metal oxide semiconductor capacitor array - - and appropriate input and output circuit constitute the basic CCD shift register. For metal bar electrode, exert the clock pulse in corresponding gate within the semiconductor electrode formation can store minority carriers potential trap. Usable light injection or electrically pumped methods will signal charge input potential trap. Then periodically change clock pulses of phase and amplitude, potential well depth is accordingly changes over time, thus make the injection of signal charge in semiconductor within directional transmission. CCD output is by reverse phase offset PN junction collect electric charge, and then reset, amplification, with discrete signal output.

The charge transfer efficiency is the most important performance parameters of the CCD with every time when one of the transfer, being transferred charge quantity and the percentage of total charge quantity said. Transfer efficiency is the maximum limit of the CCD transfer series.

Body in gully CCD the charge transfer mechanism and surface in gully CCD slightly different. Body in gully CCD called again buried ditch CCD. So-called body channel is used to store and transfer signals in gully is in charge of the semiconductor surface of a certain distance from the body form. Body in gully CCD clock frequency can be as high as hundreds of megahertz, and usually surface in gully CCD only a few MHZ.

Solid imaging, signal processing and mass storage is the three main purposes. CCD Various linear array, face array as sensor have been successfully used in astronomy, remote sensing, fax, card reading, light testing and TV camera and other fields, micro-opto-electro-mechanical CCD and infrared CCD in navigation away empty feeling, thermal imaging and other military applications showed great role. CCD signal processing both digital and analog two kinds of signal processing technology strengths, in medium precision of the radar and communication system widely. CCD also can be used as the large capacity serial storage, its access time and system capacity and manufacturing cost between semiconductor memory and disk, drum, memory between.