The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Mixed-Signal Design >> Regarding Cadence Virtuoso gpdk45nm technology spectre model file.
https://designers-guide.org/forum/YaBB.pl?num=1438593049

Message started by PS on Aug 3^rd, 2015, 2:10am

Title: Regarding Cadence Virtuoso gpdk45nm technology spectre model file.
Post by PS on Aug 3^rd, 2015, 2:10am

I am designing ampilfier circuit in cadence virtuoso using gpdk45nm technology spectre model file. I am finding difficulty in figuring out the exact mobility of either of pMOS or nMOS transistors. For example, in one of the geometrical model in file the mobility of pMOS is given as u0=0.02305+du0_p and for nMOS u0=0.01528+du0_n. In typical-typical standard process (given in file) the value for du0_p and du0_p is 0, which means that mobility of pMOS is greater than nMOS which is not possible. All the initial values of pMOS is greater than nMOS in all the geometrical models given in file. Mobility of holes can never be greater than electrons. So, how these mobility values are decided or there is another method to estimate the mobility values of nMOS and pMOS. Please reply soon.

Title: Re: Regarding Cadence Virtuoso gpdk45nm technology spectre model file.
Post by Geoffrey_Coram on Jan 25^th, 2016, 12:40pm

I think I agree that the mobility of holes should not be greater than that of electrons in a given material. However, the channel of the pMOS is not the same material as that of the nMOS: the dopants (type and concentration) will be different. In addition, some processes (I don't know specifically about yours), foundries sometimes apply caps that engineer the strain of the devices to improve the mobility.

Title: Re: Regarding Cadence Virtuoso gpdk45nm technology spectre model file.
Post by deltasigmaADC on Feb 1^st, 2016, 4:57am

There are cases when the mobility of holes can actually be found greater than electrons. Especially in strained silicon cases and when SiGe are used, this could lead to higher hole mobility.
Also based on the orientation of the Cristal and carrier flow the mobility can change.

http://www.sciencedirect.com/science/article/pii/S0961129006715903

This article will help you to know more about this