Part 2 semicon

Question 1

A device in which the charge carriers are confined entirely within a solid material is called a

Answer 1

solid-state device.

Question 2

are materials that exhibit electrical properties that are intermediate to those of conductors and insulators.

Answer 2

Semiconductors

Question 3

1833 – ______ discovered that silver sulfide, a semiconductor, has a negative temperature coefficient

Answer 3

Michael Faraday

Question 4

1835 – ______found out that certain materials have rectifying properties

Answer 4

Munk A. Rosenshold

Question 5

1874 – _____ discovered the point-contact rectifier effect while working with galena (lead sulfide)

Answer 5

Ferdinand Braun

Question 6

____________ means that the resistance of the material or device decreases as the temperature increases.

Answer 6

Negative temperature coefficient (NTC)

Question 7

_____ - ionized gas that occurs at very high temperatures

Answer 7

plasma

Question 8

_________ - occurs when the atoms have very similar quantum levels at temperatures very close to absolute zero, predicted in 1924 and experimentally observed in 1995

Answer 8

Bose-Einstein Condensate

Question 9

a superfluid phase formed by fermionic particles at low temperatures

Answer 9

Fermionic condensate

Question 10

the state of a liquid at very low temperatures close to absolute zero characterized by having zero viscosity and infinite conductivity

Answer 10

superfluid

Question 11

electrons found at the outermost shell or valence shell. The number of electrons in the outermost shell of an atom determines its valence.

Answer 11

Valence Electron

Question 12

An atom that has lost or gained electrons is called an ___ and the process is called ______.

Answer 12

ion, ionization

Question 13

The upper band is called the _______.

Answer 13

conduction band

Question 14

When a valence electron leaves an atom, it becomes a __________ in the conduction band.

Answer 14

conduction electron or a free electron

Question 15

The lower band, called the ______ consists of a series of energy levels where valence electrons can be found.

Answer 15

valence band

Question 16

Between the conduction and the valence bands is the ________.

Answer 16

forbidden band.

Question 17

The energy separation between the conduction band and the valence band is called _________.

Answer 17

energy gap

Question 18

_______ semiconductors are made of a single-crystal structure that forms a repetitive pattern.

Answer 18

Elemental

Question 19

a solid material in which the atoms are arranged in a symmetrical pattern

Answer 19

Crystal

Question 20

the periodic arrangement of atoms in a crystal

Answer 20

lattice

Question 21

Any material that is composed of only one type of crystal is called a

Answer 21

single crystal structure.

Question 22

Both silicon and germanium atoms have four valence electrons and are called

Answer 22

tetravalent atoms.

Question 23

the sharing of valence electrons among atoms in a crystal

Answer 23

Covalent bonding

Question 24

When a free electron loses energy and falls back into a hole in the valence band, the process is called

Answer 24

recombination.

Question 25

Semiconductor materials that have been refined to achieve a high degree of purity are called

Answer 25

intrinsic semiconductor.

Question 26

a “pure” semiconductor crystal that has been refined to reduce the level of impurities to a very low level

Answer 26

Intrinsic semiconductor

Question 27

is the process of altering the electrical conductivity of a semiconductor material by increasing the number of charged carriers on it, which can be achieved by adding impurity atoms into the semiconductor.

Answer 27

Doping

Question 28

A semiconductor material that has been subjected to doping process is called

Answer 28

extrinsic semiconductor

Question 29

are called donor atoms because for pentavalent atom added, a single free electron has been “donated” into the semiconductor.

Answer 29

Pentavalent atoms

Question 30

acceptor atoms.

Answer 30

trivalent

Question 31

the current in a semiconductor due to the random motion of electrons when no external electric field is applied

Answer 31

Diffusion current

Question 32

refers to the directional flow of free electrons in the conduction band. Electrons move from negative to positive.

Answer 32

Electron current

Question 33

the movement of holes in the valence band, which is opposite that of the electron current. Hole current has the same direction as the conventional current.

Answer 33

Hole current

Question 34

the type of current that has the same direction as the hole current (positive to negative); this is the preferred current direction in most circuit analysis texts.

Answer 34

Conventional current

Question 35

If a piece of intrinsic silicon is doped such that one end is p-type and the other in n-type, a _______ will be formed at the boundary between the two regions and a device called a ________ is created.

Answer 35

pn junction, diode

Question 36

refers to the region near the pn junction that is depleted or void of charge carriers.

Answer 36

Depletion region

Question 37

is the potential difference established by the electric field in the depletion region.

Answer 37

Barrier potential

Question 38

A ______ is a two terminal, nonlinear, solid-state device capable of conducting current in only one direction under normal conditions.

Answer 38

diode

Question 39

The boundary between the n and the p regions is called the __________.

Answer 39

pn junction

Question 40

The terminal of the diode connected to the p region is called the ____ while the other which is connected to the n type region is called the _____.

Answer 40

anode, cathode

Question 41

The barrier potential is also called the _______of the diode.

Answer 41

threshold voltage

Question 42

_______ refers to the process of applying a dc voltage to a semiconductor device to achieve its proper operating condition.

Answer 42

Biasing

Question 43

a type of bias that decreases the width of the depletion region. This can be achieved by connecting the more positive potential of the dc source to the p-type material and the more negative terminal of the source to the n-type material.

Answer 43

Forward bias

Question 44

If the anode of the diode is made more negative with respect to the cathode, the diode is said to be _________

Answer 44

reverse biased

Question 45

the type of bias that causes the depletion region to become wider.

Answer 45

Reverse bias

Question 46

This very small current called the ______, IS, is caused by the minority carriers in the n and p regions that are produced by thermally generated electron-hole pairs.

Answer 46

saturation current

Question 47

The saturation current is a function of _______.

Answer 47

temperature

Question 48

This current is called the ________ which is caused by surface impurities and imperfections in the crystal structure.

Answer 48

surface leakage current

Question 49

Increasing the _____ would also increase the surface leakage current.

Answer 49

reverse bias voltage

Question 50

This dramatic increase in the reverse current is called ________ which can damage the diode because of excessive heating.

Answer 50

avalanche

Question 51

The maximum reverse voltage that a diode can withstand before it breaks down is called the ____.

Answer 51

peak inverse voltage or PIV

Question 52

The general characteristic curve of a semiconductor diode can is defined by _______

Answer 52

Shockley’s equation

Question 53

static resistance, slope of the line connecting 2 points in the characteristic curve of the diode

Answer 53

DC resistance

Question 54

– also called ac resistance, the ratio of the change in the diode voltage for a given change in the diode current,

Answer 54

Dynamic resistance

Question 55

reverse bias capacitance

Answer 55

Transition capacitance

Question 56

Transition capacitance

Answer 56

Transition capacitance