Charge-Coupled Devices

Soon after the charge-coupled device was invented at Bell Labs in 1969, the knee-jerk reaction of many semiconductor researchers was, "I should have thought of that!" Almost all the required MOS fabrication techniques had been available for nearly a decade; what was needed in addition was the inspiration to apply them in assembling the appropriate configuration. This encouragement came in part from Jack Morton, who prodded his colleagues to develop a semiconductor device that was analogous to the then-popular magnetic-bubble memory. Contemporaneous work on the silicon diode array camera tube also played an important role.

That autumn, Willard S. Boyle and George E. Smith busted this conceptual block by suggesting that a linear array of MOS capacitors could be used as charge-storage and transfer devices. In October the first CCD was fabricated, a simple array of ten MOS capacitors; it performed much as predicted. Boyle and Smith published their work the following spring in the Kelt Labs Technical Journal and presented it in a few IEEE meetings - including Smith's memorable talk at the 1970 Seattle Device Research Conference.

Modifications of the basic CCD idea quickly followed, including a serious but short-lived application to computer memory. With a Bell Labs engineer, Boyle and Smith conceived the "buried channel" approach, whereby the charge is stored in the bulk silicon rather than at its interface with the silicon-dioxide surface layer. Marvin White and his colleagues at Westinghouse developed techniques to reduce noise, which eliminated a "bottleneck" in low-light-level imaging devices.

When Jim Early (who had left Bell Labs for Fairchild in 1969) encountered the buried-channel approach in 1971, he became convinced that this was the best way to proceed, as it could surmount the potential problem of charge trapping by surface-state electrons. He hired Gilbert Amelio from Bell Labs to work on buried-channel CCDs under a Fairchild contract with the U.S. Navy. The resulting devices had high sensitivity and extremely low noise. Other companies such as GE, Hughes Aircraft, RCA and Texas Instruments were involved in the race to develop CCDs, but it was Fairchild that succeeded in bringing these devices into the commercial marketplace.

This research and development led to many of the charge-coupled devices commonly in use today. Sporting millions of pixels per square inch, CCD's can now be found at the heart of digital cameras, camcorders, and professional TV cameras. They are also employed in a growing variety of scientific applications, such as at the focus of large optical telescopes like the Hubble Space Telescope and at the heart of gigantic particle detectors used in high-energy physics.

Exercise 5

Translate the synonyms.

1. device, apparatus, equipment;

2. to apply, to use, to utilise;

3. to assemble, to gather, to collect;

4. to begin, to start, to commence;

5. to store, to keep;

6. simple, easy;

7. to change, to modify, to alter;

8. to trap, to catch, to grasp;

9. to reduce, to lower, to decrease;

10. to result in, to lead to;

11. equal, similar, same;

12. to stop, to cease, to quit, to discontinue;

13. to transmit, to carry, to transport, to conduct, to convey;

14. to select, to choose, to pick, to elect, to opt;

15. to oscillate, to vibrate, to fluctuate, to swing;

16. to associate, to connect, to join, to link, to unite;

17. to decline, to refuse, to reject.

Exercise 6

Make up alternative questions to the text.

LESSON 15

Exercise 1

Translate the following words paying attention to word-building affixes.

Equal, equality, equally, equation, non-equal, similar, similarly, dissimilar, similarity, understand, misunderstanding, understood, understandable, establishment, establishing, establish, re-establish, re-established, confine, confinement, confining, confined, confines, mobile, mobility, mobilised, immobilising, mobilisation, versatile, versatility, allow, allowance, allowing, allowed, extreme, extremist, extremity, extremely, measure, measurements, measuring, immeasurably, measurable, possible, possibility, possibly, impossible, variety, vary, variant, variety, variation, varying, lay, laid, overlaying, layer, thickest, thickness, thick, thicken, thickening, thicker.

Exercise 2

Translate the following sentences paying attention to adjectives and adverbs.

1. The new architecture is a little more complex than conventional designs. 2.The telecommunication industry being in trouble, some parts are in less trouble than others. 3. Though at the moment it is more expensive to communicate with light than with electric current, the day is coming when only optical technologies will be able to keep up with the demands of ever-more-powerful microprocessors. 4. So, thinner – and especially longer – wire means a lower bit rate. 5. Such spacing raises the spectre of problems shared with electrical wires: as they get closer and operate at higher rates, the threat of electrical interference between the adjacent channels increases. 6. A sandwich of metal-semiconductor-metal creates MSM photodetectors that work much the same way, at a higher speed than p-i-n photodiodes but with less sensitivity. 7.LEDs, unfortunately, are not as useful as more powerful, more focused lasers. 8.The progression should be from expensive, intensive computer systems to simpler, cheaper ones, as well as from longer to shorter distances. 9. The larger the amplitude, the more positive the dc component. 10. The amount of distortion is mostly set by IC and as its band-width is approximately four to five times higher than the highest oscillation frequency of most fundamental mode AT-cut crystals, the effect of IC band-width is negligible. 11. It is true in the latter case that too much I really is better than too little – but not much better, and AB still comes a poor third in linearity to Classes A and B. 12.The substrates used today for GaN, such as sapphire, are all relatively costly or poorly matched to the semiconductor. 13. More importantly, it brings closer to reality the mass production of devices such as blue-violet laser diodes suitable for the next generation of home digital video consoles. 14. Successfully extracting maximum power from a cluster is itself not an easy task. 15. The use of multiple carriers makes the most efficient use of available spectrum, data rates being higher when multiple bits are sent on multiple channels at the same time. 16. The closer the wires (in both dimensions), the greater the capacitance and the longer it takes for the signal to propagate down the line.

Exercise 3

Match Ukrainian translations to the following English phrases.

1. III-V compounds	1. складнi напiвпровiдники
2. tetrahedral structure	2. широкi світловi канали
3. carrier mobilities	3. хiмiчнi сполуки елементiв III – V груп
4. versatile band structures	4. квантовi кишенi
5. high-frequency oscillators	5. сканери штрихкоду
6. higher performance	6. занадто вузькi дiлянки
7. narrow-band-gap	7. багаторезонаторний
8. inner layer	8. чотиригранна структура
9. liquid-phase epitaxy	9. iндекси заломлення
10. molecular-beam epitaxy	10. рухливiсть носiїв
11. tightly confined spaces	11. вузька енергетична заборонена зона
12. quantum wells	12. високочастотнi генератори
13. multiple-cavity	13. рiдинна епiтаксiя
14. surface emitting	14. структури з рiзними енергетичними зонами
15. compound semiconductors	15. внутрiшнiй шар
16. refractive indices	16. поверхневе випромiнювання
17. bar-code scanners	17. вищi робочi характеристики
18. vast highways of light	18. молекулярна епiтаксiя

Exercise 4

Pay attention to translation of the following phrases.

1. flash away at the heart -	спалахують у серцi;
2. elements in fiber-optic systems that span the globe - елементи у волоконно-оптичних системах, що оповивають земну кулю.

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