Chapter 5. Semiconductor (полупроводник)

Exercise 1. Read and translate the text, using the words below.

A semiconductor is a material that has an electrical conductivity due to flowing electrons (as opposed to ionic conductivity) which is intermediate in magnitude between that of a conductor and an insulator. Devices made from semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, and many other devices. Semiconductor devices include the various types of transistor, solar cells, many kinds of diodes including the light-emitting diode, the silicon controlled rectifier, and digital and analog integrated circuits. Similarly, semiconductor solar photovoltaic panels directly convert light energy into electrical energy. In a metallic conductor, current is carried by the flow of electrons. In semiconductors, current is often schematized as being carried either by the flow of electrons or by the flow of positively charged "holes" in the electron structure of the material. Actually, however, in both cases only electron movements are involved.

Common semiconducting materials are crystalline solids but amorphous and liquid semiconductors are known. These include hydrogenated amorphous silicon and mixtures of arsenic, selenium and tellurium in a variety of proportions. Such compounds share with better known semiconductors intermediate conductivity and a rapid variation of conductivity with temperature, as well as occasional negative resistance. Such disordered materials lack the rigid crystalline structure of conventional semiconductors such as silicon and are generally used in thin film structures, which are less demanding for as concerns the electronic quality of the material and thus are relatively insensitive to impurities and radiation damage. Organic semiconductors, that is, organic materials with properties resembling conventional semiconductors, are also known.

Silicon is used to create most semiconductors commercially. Dozens of other materials are used, including germanium, gallium arsenide, and silicon carbide. A pure semiconductor is often called an “intrinsic” semiconductor. The electronic properties and the conductivity of a semiconductor can be changed in a controlled manner by adding very small quantities of other elements, called “dopants”, to the intrinsic material. In crystalline silicon typically this is achieved by adding impurities of boron or phosphorus to the melt and then allowing the melt to solidify into the crystal. This process is called "doping".

Words to be remembered.

to rectify–исправлять; выверять; выпрямлять

hole–отверстие, полость, канал; дыра

solid–твёрдое тело

silicon–кремний

arsenic–мышьяк

compound–1. состав, соединение 2. составной; сложный 3. смешивать, соединять

insensitive–нечувствительный

intrinsic–внутренний; свойственный; существенный

intrinsic germanium–германий с собственной электропроводностью

boron–бор

to solidify–затвердеть; делать твёрдым

doping–1. добавление присадок; введение добавок; легирование 2. обмазывание; допирование

dopant–легирующая примесь; диффузант; допант

Exercise 2. Answer the following questions.

1. What is a semiconductor?

2. What do semiconductor devices include?

3. Into what energy do semiconductor solar photovoltaic panels directly convert light energy?

4. In what conductor current is carried by the flow of electrons?

5. What are common semiconducting materials?

6. What lacks the rigid crystalline structure of conventional semiconductors?

7. Silicon is used to create most semiconductors commercially, isn`t it?

8. Is a pure semiconductor often called an “intrinsic” or “extrinsic” semiconductor?

9. How can the electronic properties and the conductivity of a semiconductor be changed?

10. What is “doping”?

Exercise 3. Match the words on the left with the words on the right.

1. electrical conductivity	1. энергия света
2. semiconductor devices	2. радиационный вред
3. solar cell	3. электронные свойства
4. light-emitting diode	4. электрическая проводимость
5. light energy	5. маленькие количества
6. electron movement	6.полупроводниковые устройства
7. negative resistance	7. солнечный элемент
8. radiation damage	8. светоиспускающий диод
9. small quantities	9. отрицательное сопротивление
10. electronic properties	10. движение электронов

Exercise 4. Match Russian and English terms in columns A and B.

A:semiconductor, insulator, conductor, device, digital, mixture, compound, conductivity, dozen, pure

B:беспримесный, полупроводник, дюжина, соединение, цифровой, изолятор, смесь, проводник, устройство, проводимость.

Exercise 5. Substitute Russian words for the English ones.

1. A semiconductor is a material that has an electrical проводимость due to the flowing electrons.

a) conductor

b) conductivity

c) conducting

2. Semiconductor devices включают various types of transistor, solar cells, many kinds of diodes.

a) include

b) exclude

c) switch on

3. In a metallic conductor, ток is carried by the flow of electrons.

a) current

b) currency

c) courage

4. Common semiconducting materials are crystalline solids but amorphous and жидкие semiconductors are known.

a) watered

b) plasmic

c) liquid

5. Such disordered materials lack the rigid crystalline структура of conventional semiconductors.

a) foundation

b) structure

c) form

6. Дюжина of other materials is used, including germanium, gallium arsenide and silicon carbide.

a) dozen

b) decade

c) twelve

7. This process называется “doping”.

a) is situated

b) is called

c) is located

Exercise 6. Translate the following sentences from Russian into English.

1. Полупроводник – это материал, который имеет электрическую проводимость. 2. Устройства, сделанные из полупроводниковых материалов, являются основой современной электроники, включая радио, компьютеры, телефоны и многие другие приборы. 3. Полупроводниковые устройства включают различные виды транзисторов, солнечных элементов, много видов диодов, включая светоиспускающий диод. 4. Полупроводниковые солнечные панели преобразуют световую энергию в электрическую. 5. Известны аморфные и жидкие проводники. 6. Кремний используется для коммерческого производства полупроводников. 7. Используются также дюжины других материалов, включая германий, арсенид галлия и карбид кремния. 8. Электронные свойства и проводимость полупроводника можно изменить, добавив небольшие количества других элементов, называемых присадками (примесями). 9. Такой процесс называется добавление присадок (легирование). 10. В металлическом проводнике ток движется при помощи потока электронов.

Exercise 7. Express the main idea of the text in several sentences.