# Voltage inside an semiconductor chip?

1. Jul 12, 2004

### shankar

i have a basic question about IC

we give 5 volt in general in to an IC but the size of the IC is in nano measure if this 5 volt is given to such a small area the volt/area will become very large and how the IC still functions with out burning.

let me know how this happens .

2. Jul 12, 2004

### Tyger

Voltage is the "across" quantity, so the important thing is the thicknes of the semiconductor junction. It doesn't need to be very thick to withstand 5 volts. The "through" quantity is current, which is usually in the miliampere range. So the current density ne charge flux is not that great.

3. Jul 13, 2004

### shankar

ya you are right but how to justify the voltage factor. As you said, yes it is across factor but till we nned to justify voltage if not volt/area. howto do it.

4. Jul 25, 2004

### rayjohn01

chip voltages

There are several factors determining voltage -- but not area --
in cases where normal transistors are used there are breakdown conditions to think of since some junctions are reverse biassed and they are not very thick.
In Cmos circuits there are limits to the gate potental before 'punch through'
of the gate.
But there is also a question of circuit speed and power, in digital circuits such as CMOS the internal voltages are switched from rail to rail if this voltage is smaller and for given drive conditions ( size and doping defined ) the transit times of the nodes can be shorter and dissipation reduced.
Watches are a good example employing thousands of transisitors with voltages as low a 1 volt and currents < 1 microAmp, but the clock is only
a few 10's of kilohertz.