Listen to the text again and decide whether the statements are true or false. Use the expressions of agreement and disagreement
1Aluminium is used as an ingredient of plastic encapsulants for integrated circuits.
2Because of its high resistivity aluminium metal lines provide conductivity between components.
3Gold is more malleable and ductile than silicon.
4For IC metallization aluminium is used without any dopants.
5Silicon is most commonly used in integrated circuits.
6Silicon dioxide is the main component of ordinary sand.
7The advantage of gold wires during the encapsulation process is its hardness.
Match the words on the right to the words in the left.
| 1integrated | Abehavior |
| 2dopant | Bcircuits |
| 3plastic | Cducility |
| 4lightweight | Delements |
| 5semiconductor | Eencapsulants |
| 6excellent | Flayers |
| 7electrical | Gmanufacturing |
| 8dielectric | Hmetal |
Speak on the semiconductor materials, comparing aluminium, silicon, gold. Use word-combinations in Exercise 4.
FINAL TEST
Agree or disagree with the following statements.
1Conduction properties of semiconductors don’t depend on temperature.
2The concentrations of electrons and holes are different in an intrinsic semiconductor.
3The minority carriers are responsible for the conduction properties of the material.
4The material is called n-type if free holes are created in it.
5The addition of pentavalent impurities greatly increases the conductivity of the intrinsic semiconductor.
6In P-N junction current flows in forward and reverse direction.
7Due to its properties semiconductors are widely used in optoelectronic devices.
Choose the correct answer.
1The current flow in an intrinsic semiconductor consists of ...
Aelectron current
Belectron and hole current
Chole current
2In an intrinsic semiconductor at temperature above absolute zero, there will be electrons moving into ... which can produce current.
Avalence band
Bband gap
Cconduction band
3... is a process of adding impurities to a semiconductor.
Adoping
Bexcitation
Cincreasing
4The combination of free electrons with holes at the p-n junction leads to the formation of ...
Anegative ions
Bpositive ions
Cextra electrons
5Intrinsic semiconductors have ...
Alarge concentration of holes
Blarge concentration of electrons
Cequal concentration of electrons and holes
6In an intrinsic semiconductor electrons and holes move in ... direction.
Athe same
Bopposite
7A large atoms brought together into a regular array is called ...
Aenergy level
Bcrystal lattice
Cband gap
Translate the following sentences from English into Russian.
1According to the band theory of solids electrons can reach the conduction band and contribute to electrical conduction.
2The electrical conductivity depends on the mobility of the charged carriers and their concentration.
3In a p-type semiconductor conductivity is increased due to the fact that the dopant produces extra vacancies or holes.
4A “depletion region” is created when electrons diffuse across to combine with holes near the junction.
5After an impurity is added to a semiconductor the material is called extrinsic.
Translate the following sentences from Russian into English.
1Каждый электрон атома может иметь определенную энергию, так называемый энергетический уровень.
2Как электроны так и «дыры» могут двигаться под влиянием внешнего напряжения.
3Поток электрического тока зависит от ускорения частиц при воздействии внешнего электрического поля.
4Тип носителя заряда, содержащийся в большей концентрации в материале, иногда называется основным носителем.
5Хотя неосновные носители заряда играют незначительную роль в электрической проводимости, они могут быть важны при выпрямлении и работетранзистора в полупроводниках.