Semiconductor

Question 1

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

Answer 1

solid-state devices

Question 2

materials whose electrical properties are intermediate to those of conductors and insulators

Answer 2

semiconductors

Question 3

The _________ of a semiconductor
material is between that of a good
conductor and that of an insulator

Answer 3

conductivity

Question 4

What is the most commonly used semiconductor material?

Answer 4

silicon

Question 5

Electrons “orbit” the nucleus in quantized ________

Answer 5

energy levels

Question 6

• The orbits are grouped into energy bands known
  as _________________

Answer 6

shells

Question 7

• In a crystalline solid, the energy levels of the system form a set of ____.

Answer 7

bands

Question 8

• Valence electrons are found in the
  _________________.

Answer 8

valence band

Question 9

• An electron that acquires sufficient energy, can be a free electron in the _________________.

Answer 9

conduction band

Question 10

• Between the valence and the
  conduction band is the__________

Answer 10

forbidden band

Question 11

__________________ – energy difference between the two bands, also known as ________________

Answer 11

energy gap, band gap

Question 12

Generally, semiconductors have a ________ temperature coefficient of resistance.

Answer 12

negative

Question 13

For insulators, the Eg is typically greater than ____ at 300 K

Answer 13

5 eV

Question 14

• For ________, Eg is from less than 1 eV to a little more than 2 eV

Answer 14

semiconductors

Question 15

The energy gap is __________dependent.

Answer 15

temperature

Question 16

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

Answer 16

crystal

Question 17

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

Answer 17

single crystal structure

Question 18

• The sharing of valence electrons, that holds the atoms together in a crystalline material is called___________________.

Answer 18

covalent bonding

Question 19

Charges that contribute to current generation in the semiconductor are called ___________________________.

Answer 19

charge carriers

Question 20

is vacancy left by an electron in the valence band. It has a unit positive
charge.

Answer 20

hole

Question 21

When an electron loses energy, it
goes back to a lower energy level,
filling up a hole, in a process called
_________________.

Answer 21

recombination

Question 22

charge carriers in semiconductor materials:

Answer 22

free electrons, holes

Question 23

A “pure” semiconductor crystal that has been refined to reduce the level
of impurities to a very low level is called ____________________________ .

Answer 23

intrinsic

Question 24

free electrons available due to external causes

Answer 24

intrinsic carriers

Question 25

ability of free carriers to move throughout the material

Answer 25

mobility

Question 26

Refers to the process of altering the electrical properties of a semiconductor material by the addition of impurity atoms.

Answer 26

doping

Question 27

results when a semiconductor is doped with pentavalent (donor) atoms

Answer 27

N-type Semiconductor

Question 28

produced when a semiconductor is doped with trivalent (acceptor) atoms

Answer 28

p-type semiconductor

Question 29

The random motion of the charge carriers in the absence of an external field gives rise to _______

Answer 29

diffusion current.

Question 30

* In the presence of an external field, the charge carriers move in response, establishing the _______

Answer 30

drift current.

Question 31

* The first junction diode, transistor and integrated circuit were made from what semiconductor material?

Answer 31

germanium

Question 32

The minimum amount of energy required by a valence electron to become a conduction electron is called

Answer 32

band gap

Question 33

is the most basic semiconductor device.

Answer 33

pn junction diode

Question 34

– connected to p-type

Answer 34

anode

Question 35

– connected to n-type

Answer 35

cathode

Question 36

– boundary between the p- and n-type materials

Answer 36

pn-junction

Question 37

The diffusion of electrons across the pn junction from the n- to the p-type material gives rise to the formation of the ________________________.

Answer 37

depletion region

Question 38

The charges in the depletion region establishes an electric field and a potential difference called the _________________.

Answer 38

barrier potential

Question 39

The barrier potential equals the ______________________ of the diode.

Answer 39

knee voltage

Question 40

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

Answer 40

biasing

Question 41

Anode more positive than cathode Diode conducts significant current Diode has low resistance

Answer 41

Forward bias

Question 42

* Cathode more positive than anode * Diode does not conduct * Diode has very high resistance

Answer 42

reverse bias

Question 43

When a diode is already conducting, the voltage across the diode equals its ________________________.

Answer 43

forward voltage

Question 44

The saturation current is a function of ______________________.

Answer 44

temperature

Question 45

________________________ – caused by impurities and crystal imperfections

Answer 45

crystal defect

Question 46

* Leakage current is directly proportional to the _____________________

Answer 46

applied voltage

Question 47

The minority carriers produce a very small _________________________, IS

Answer 47

current

Question 48

__________ – the dramatic increase in current in the reverse bias region caused by extremely high bias voltage.

Answer 48

breakdown

Question 49

* The region of positive and negative charges in a junction diode that is devoid of charge carriers is called

Answer 49

depletion region

Question 49

The voltage that exits due to the electric field established by the charges in the depletion region

Answer 49

barrier potential

Question 50

The external voltage that must be applied at which the diode current increases significantly

Answer 50

threshold voltage

Question 51

* The maximum voltage that a diode can sustain in the reverse bias before entering the breakdown region.

Answer 51

peak inverse voltage

Question 52

The voltage at which significant current flows through a reverse biased diode

Answer 52

breakdown voltage

Question 53

The breakdown mechanism for diodes that are highly doped occurring at relatively lower reverse bias voltage is called

Answer 53

zener breakdown

Question 54

Predominant capacitive effect in a reverse biased diode is the

Answer 54

transition capacitance

Question 55

*When a diode is conducting in the forward bias region, the voltage across the diode

Answer 55

equals the barrier potential

Question 56

* A process of converting ac voltage into pulsating dc

Answer 56

rectification

Question 57

* A diode circuit that removes a portion of the waveform above/or below a specified level

Answer 57

limiter

Question 58

A dc restorer is more commonly known as

Answer 58

clamper

Question 59

What component can be found in a clamper but not in a clipper?

Answer 59

capacitor

Question 60

* Special purpose diode designed to work in the ____________ region

Answer 60

reverse breakdown

Question 61

*Used in voltage regulator circuits as ______________

Answer 61

reference voltage

Question 62

Zener region can be controlled by varying the ___________________

Answer 62

amount of doping

Question 63

The response of human eyes on visible light has a peak at what color?

Answer 63

green

Question 64

Which semiconductor has the most number of intrinsic carriers per unit volume at room temperature?

Answer 64

germanium