Dependence of propogation delay of a gate on the feature siz

[Resistance]

I want to know what will be the factors which influence the propogation
delay through a gate?

For current lib which is available we can see it from .lib the RC
value..

My question is to know the various factors influencing the delay with
decresing feature size...??????

Regards

 

[SkyHigh]

Re: Dependence of propogation delay of a gate on the feature

To constitute the propagation delay THROUGH a logic gate, consider the following factors:

A logic gate is made up of several transistors, so the gate-bulk capacitance, gate-source capacitance and gate-drain capacitance per transistor are parasitic capacitances that constitute propagation delay.

The poly-Si and metal layers that interconnect the gates and drains between transistors, inside a logic gate, exhibit load capacitance (inclusive of fringing capacitance) that constitute propagation delay.

The magnitude of the threshold voltage (Vth) and the supply voltage (Vdd) used can affect the switching speed, thus propagation delay.

The fan-out or the load capacitance perceived at the output of the logic can also constitute propagation delay.

The smaller the transistors, the higher the switching speed, at lower Vdd and Vth, with leakage becoming more significant in percentage. The propagation delay is also relatively shorter. All these are scaled carefully.

 

[Resistance]

Re: Dependence of propogation delay of a gate on the feature

Hi ,
so u come to say that the delay decrease with decreaing featurewsize.. very true until 135 micro beyond that am not sure? I personally the thinking this dec in deal will not be uniform beyond this??

regards

 

[joe2moon]

Re: Dependence of propogation delay of a gate on the feature

------------------------------------------------------------------------------
Key Parameters
- Vdd
- Lgate,drawn
- Tox
- Vth
- Isat
- Cj

Please refer to the following link, and you will get some ideas
-------------------------------------------------------------------------------
**broken link removed**

 

[spauls]

Re: Dependence of propogation delay of a gate on the feature

DSM delay causes are
(1) Incorrect process variations
(2) Multi voltage islands in same chip
(3) Multi temperature drops (Dynamic IR drop)
(4) Incorrect transition
(5) Imbalance output loads.