# How to simulate the depletetion layer of a PN junction using TCAD?

#### Cascoded

##### Newbie
Hello everyone.

This is my first post in this forum. I have seen there is a lot of interesting information about IC design.

However, I will need to carry out TCAD simulation (which I have never done before) and I would be very grateful if someone could provide me with some useful tutorials or user guides where I can learn how to calculate the width of the depletion layer of a PN junction biased at a given voltage using Silvaco software.

Regards.

#### dick_freebird

If you only want to calculate the depletion width,
based on doping and bias, in a 1-D form then
there are charts and formulae that are easy to
use.

2D or 3D, you're stuck with TCAD pretty much
(maybe some formulae for curved junctions'
breakdown, etc.).

The steps are first, meshing (you have to draw
or import the physical structure and region
properties) and second, assignment of boundary
conditions. This I know from feeding layouts to
people who actually do TCAD work. This is where
to start, and a good bit of tedium.

a lot of provided tutorials. It would be surprising
if the same wasn't true of the TCAD tools. Have
you exhausted that material, or even found it in
your installation documents and tutorials pile?
Gone on Silvaco's support pages?

#### Cascoded

##### Newbie
If you only want to calculate the depletion width,
based on doping and bias, in a 1-D form then
there are charts and formulae that are easy to
use.

2D or 3D, you're stuck with TCAD pretty much
(maybe some formulae for curved junctions'
breakdown, etc.).

The steps are first, meshing (you have to draw
or import the physical structure and region
properties) and second, assignment of boundary
conditions. This I know from feeding layouts to
people who actually do TCAD work. This is where
to start, and a good bit of tedium.

a lot of provided tutorials. It would be surprising
if the same wasn't true of the TCAD tools. Have
you exhausted that material, or even found it in
your installation documents and tutorials pile?
Gone on Silvaco's support pages?

Actually, I do not have access to Silvaco tools yet, but I wanted to get started straight away.

So, do you think that using basic 1D equations I will be able to (accurately) determine whether punch through occurs between the junction and neighboring nwells?