Contents
What is channel length modulation and why it is important in present day Si based CMOS transistors?
Channel-length modulation is important because it decides the MOSFET output resistance, an important parameter in circuit design of current mirrors and amplifiers.
How does temperature affect threshold voltage?
As temperature rises, the threshold voltage decreases and the subthreshold leakage current increases exponentially with increase in temperature. So this leakage becomes a severe problem in the case of devices operating at high temperatures.
Why is threshold voltage of pMOS negative?
Holes can be attracted by negative voltage. So we must have to apply negative voltage to form the p-channel beneath the gate. That is why thresold of pMOS is negative.
What is the threshold voltage for CMOS technology?
Sub-threshold non-scaling and standby power limitations bound the threshold voltage to a minimum of 0.2 V at the operating temperature.
How does threshold voltage depend on the size of the transistor?
This is due to charge sharing phenomenon and induced barrier lowering. The effect of the the shrinking the size of the transistor on the threshold voltage was treated intensively in the .literature both theoretically and experimentally. Even the effect of Vth lowering with reduced channel length is included in the text books of the MOS devices.
Can a channel length increase or decrease voltage?
The short answer is – yes. The slightly longer answer, it depends on the fabrication details of the transistor and it’s targeted use case. In all cases, below a critical length V T H decreases with decreasing length. However once this critical length is met the V T H can increase, stay the same or decrease.
What are the trends in CMOS logic technology?
Trends of power supply voltage Vdd, threshold voltage Vth, and gate oxide thickness tox, versus channel length for CMOS logic technologies.