Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Need nfo on Antenna Effect in Layout?

Status
Not open for further replies.

kumar123

Member level 3
Joined
Sep 5, 2006
Messages
57
Helped
9
Reputation
18
Reaction score
6
Trophy points
1,288
Activity points
1,639
Hi ,

Could anybody help me providing docs or info on this topic
like what is the antenna effect? how it arises, and what is the approach for avoiding it

Thanks for your support
Kiran Kumar
 

DZC

Full Member level 3
Joined
Sep 12, 2006
Messages
150
Helped
13
Reputation
26
Reaction score
4
Trophy points
1,298
Activity points
2,122
As far as I know,Antenna Effect happens when you make a poly layer of a too much area.Because during some subsequential process the larger poly will collect more electron(behaves somewhat like an antenna).If the excessive electron lead to a gate voltage exceeds the breakthrough voltage,it will damage the device.
So to avoid the antanna effect,you should avoid large poly area.And if you have to make a big transistor,you can split the gate and connect them with metal layers.
Hope this will help.
 

evilguy

Full Member level 4
Joined
Sep 21, 2005
Messages
206
Helped
21
Reputation
42
Reaction score
7
Trophy points
1,298
Activity points
2,768
antena effect happen if your poly connect to long metal wire. so avoid connecting gate with long metal wire. You can use jumper to prevent antenna effect if you need to connect gate to long metal wire.
 

huojinsi

Full Member level 5
Joined
Jan 21, 2005
Messages
256
Helped
25
Reputation
50
Reaction score
6
Trophy points
1,298
Activity points
2,216
DZC's explanation is very clear!
 

hauntedhunter

Newbie level 4
Joined
Nov 15, 2005
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,326
Antenna effect can happen for any large interconnect(not only poly)connected to the gate of a transistor.Because the large metal area can accumulate charges during etching and will find a way to dissipate after that layer is processed.That charge might be too much for the thin gate to handle and may damage it.
 

rush3k

Member level 1
Joined
Mar 31, 2006
Messages
38
Helped
8
Reputation
16
Reaction score
0
Trophy points
1,286
Activity points
1,507
With regards to gate, antenna effect on the gate occurs when the poly is "edge intensive" ... meaning the poly lines used results in a lot of edges on the device due to STI (shallow trench). When this happens, there's a more electric field seen around the poly and so the charge deposited causes the oxide to start to breakdown (read about hole traps and electron traps). Also, because there's more surface area, the poly is collecting more plasma ions that contribute to amount of charge on it.

Antennas are used in designing test structures, just how the poly is able to collect plasma, so it is with other layers ... especially metals. When metal1 is designed in antenna form, it results in shallow trenches formed around the metal1 structure and so more electric field and more charge.

See **broken link removed** link.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top