WHAT IS AN INTEGRATED CIRCUIT?

An IC is complete electronic circuit in which both the active & passive components are fabricated on a tiny single chip of SILICON.

Active components are those components which are able to produce gain.

Passive components are those components which do not have this ability.

HISTORY

Tremendous changes in Electronic circuitry starts after the invention of Triode by L.D Forest in 1907.

Invention of Transistor in 1948 by W.H Bardeen & I.Bardeen electronic circuit became reduced in size.

In early 1960 field of microelectronic born to meet the requirement of Military.

CONTD…

J.S Kilby was first person who develop IC.

Soon after Robert Noyce fabricate a complete IC including interconnection on single chip.

SCALE OF INTEGRATION

SSI – small scale integration

MSI – medium scale integration

LSI – large scale integration

VLSI – very large scale integration

ULSI – ultra large scale integration

GSI – giga scale integration

CIRCUITS PER CHIP

SSI < 12 (No. of comp.less than 50) MSI 12 – 99 (No. of comp. 50 – 5000) LSI 100 – 9999 (No. of comp. 5000 – 100000) VLSI 10000 – 99999 (No. of comp. 100000 –

1000000) ULSI 100000 – 999999 (No. of comp. 1000000 –

10000000) GSI >1000000 (No. of comp. 100000000)

CLASSIFICATION OF IC’s

On structure basis On function basis

ON STRUCTURE BASIS

MONOLITHIC INTEGRATED CIRCUITSTHICK & THIN FILM INTEGRATED

CIRCUITSHYBRID / MULTICHIP INTEGRATED

CIRCUITS

MONOLLITHIC IC

The word monolithic means “SINGLE STONE” or more appropriately “Single solid structure’.

In this all circuit all components are fabricated within single continuous piece of silicon crystalline material called “WAFER” or “SUBSTRATE”

ADVANTAGES & DISADVANTAGES OF MONOLITHIC IC’s

These have advantage of lower cost and high reliability.

However they have poor isolation between the components, short range of passive components, no flexibility of circuit design.

INDUCTORS cannot be fabricated.

THICK & THIN FILM IC

The difference between between thick & thin film are not their relative thickness but method of depositing film.

These IC’s are not formed within single silicon wafer but surface of an insulating substrate such as glass or ceramic materials.

Only passive components are formed through thick or thin film.

THIN FILM IC

Such circuits are constructed by depositing film of conducting material through a mask on the surface of substrate made of glass or ceramic.

Following methods are used to produce thin film.

VACUUM EVAPORATION CATHODE SPUTTERING

THICK FILM IC

These are printed thin film circuits.Silk screen printing techniques are

employed to create the desired circuit pattern on the surface of substrate

ADVANTAGES & DISADVANTAGES OF FILM IC’s

These have advantages of forming passive components of broader range.

High tolerance Isolation is betterBetter high frequency performance.

CONTD…

Not able to fabricate active componentsComparatively higher costLarger physical size

HYBRID IC

These IC’s are formed either by interconnecting a number of individual chips or by combination of film & monolithic ICs

They have chief advantage high flexibility but too much expensive for mass production and least reliability.

ON FUNCTION BASIS

LINEARDIGITAL

LINEAR IC’s (LICs)

These also referred as “Analog IC”.They possess much high reliabilityTheir use is much less as compared to

digital and mostly used in military and industrial application

USE OF LIC’s

Operational amp. Power amp. Microwave amp. Voltage comparators

Small – signal amp. RF & IF amp. Multipliers Voltage regulators

DIGITAL IC’s

About 80% of IC market has been captured by digital IC which is mostly used in computer IC

Digital IC contain circuits whose input and output voltages are limited to 2 possible level – high and low

USES OF DIGITAL IC’s

Digital circuits Flip – flops Counters Clock chips

Calculator chips Memory chips Microprocessors

ADVANTAGES OF IC’s

Extremely small physical size

Very small weight Reduced cost Extremely high reliability Increased response time &

speed Low power consumption Easy replacement Higher yield

DRAWBACK OF IC’s

Coils & inductors cannot be fabricated IC’s function are fairly low voltageThey handle only limited amount of powerThey are quite delicate and cannot

withstand rough handling or excessive heat