1 Aluminium is used as an ingredient of plastic encapsulants for integrated circuits.
2 Because of its high resistivity aluminium metal lines provide conductivity between components.
3 Gold is more malleable and ductile than silicon.
4 For IC metallization aluminium is used without any dopants.
5 Silicon is most commonly used in integrated circuits.
6 Silicon dioxide is the main component of ordinary sand.
7 The 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.
1 Conduction properties of semiconductors dont depend on temperature.
2 The concentrations of electrons and holes are different in an intrinsic semiconductor.
3 The minority carriers are responsible for the conduction properties of the material.
4 The material is called n-type if free holes are created in it.
5 The addition of pentavalent impurities greatly increases the conductivity of the intrinsic semiconductor.
6 In P-N junction current flows in forward and reverse direction.
7 Due to its properties semiconductors are widely used in optoelectronic devices.
Choose the correct answer.
1 The current flow in an intrinsic semiconductor consists of...
A electron current
B electron and hole current
C hole current
2 In an intrinsic semiconductor at temperature above absolute zero, there will be electrons moving into... which can produce current.
A valence band
B band gap
C conduction band
3... is a process of adding impurities to a semiconductor.
A doping
B excitation
C increasing
4 The combination of free electrons with holes at the p-n junction leads to the formation of...
A negative ions
B positive ions
C extra electrons
5 Intrinsic semiconductors have...
A large concentration of holes
B large concentration of electrons
C equal concentration of electrons and holes
6 In an intrinsic semiconductor electrons and holes move in... direction.
A the same
B opposite
7 A large atoms brought together into a regular array is called...
A energy level
B crystal lattice
C band gap
Translate the following sentences from English into Russian.
1 According to the band theory of solids electrons can reach the conduction band and contribute to electrical conduction.
2 The electrical conductivity depends on the mobility of the charged carriers and their concentration.
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3 In a p-type semiconductor conductivity is increased due to the fact that the dopant produces extra vacancies or holes.
4 A depletion region is created when electrons diffuse across to combine with holes near the junction.
5 After an impurity is added to a semiconductor the material is called extrinsic.
Translate the following sentences from Russian into English.
1 , .
2 .
3 .
4 , , .
5 , .
