1. Teacher Settani Gabriele Montinaro & Giulio Micieli CLIL ELETTRONICA
SEMICONDUCTOR

2. INTRODUCTION
Some materials conduct eletric charge better than insulators but not as well as conductors. These materials are called
SEMICONDUCTORS

3. 3 POINTS: STRUCTURE CONDUCTIVITY DOPING
SEMICONDUCTORS
3 POINTS:
STRUCTURE
CONDUCTIVITY
DOPING

4. STRUCTURE OF THE SEMICONDUCTORS
An intrinsic semiconductor is a sufficiently pure semiconductor
The most used semiconductors is silicium

5. SILICIUM

6. The silicium has like symbol Si

7. In atoms of the semiconductors (germanium, silicon) the valence electrons is not free to move through the volume of the material, but they form a covalent bond that alloy with of atoms of the semiconductor in a crystalline structure.

8. electric charge while hole are
For effect of the breach of the covalent bond in the semiconductor two types of charge carriers are originated.
Free electron are negative
electric charge while hole are
positive electric charge

9. CONDUCTIVITY OF THE SEMICONDUCTORS
In semiconductors there are two types of current. The first type of current is the classic electric current drift current, the second one happens for the phenomenon of the spread electrical worker.

10. There are two types of doping: P-TYPE N-TYPE

11. It is possible to add very small amounts of certain impurities such as arsenic or phosphorus which have more electrons per atom than silicon.
In this way extra free electrons are produced that can move and form an electric current.

12. These semiconductors are known as N-TYPE semiconductors becuase of the negative charge of the electrons

13. Another type of semiconductors is formed by adding small quantities of other impurities such as aluminium or gallium which have fewer electrons per atom than silicon

14. These semiconductors are called P-TYPE
These impurities take electrons away from a few atoms of the semiconductors, increasing the number of holes.
These semiconductors are called
P-TYPE
Referring to the positive charge associated with the holes.

15. The End