Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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.

Register Log in

what is difference between N - active and N + implantation?

Status
Not open for further replies.

020170

Full Member level 4
Joined
Jan 31, 2005
Messages
231
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,298
Activity points
2,225
In CMOS process, I know N-ch mos consist of N+ diffususion and poly

but Some process layout technology, it is used N ACTIVE layer with N+ implantation layer to construct N MOSFET.

I don't know why N+ implantation layer used in CMOS process, for forming N MOSFET.

to form N MOSFET, is it enough to use N ACTIVE layer?

why does it need N+ implatation to form N MOSFET?

what is the role of N+ implatation layer?

thanks
 

sunking

Advanced Member level 3
Joined
May 25, 2004
Messages
874
Helped
70
Reputation
140
Reaction score
23
Trophy points
1,298
Activity points
6,283
yes, N+ diff form the NMOS.
and most the process neede active layer will have a Boolean calculation to form the N+ mask finally.
 

Teddy

Advanced Member level 1
Joined
Sep 15, 2004
Messages
461
Helped
103
Reputation
206
Reaction score
62
Trophy points
1,308
Activity points
3,861
Re: what is difference between N - active and N + implantati

Active or sometimes called diff is area which specifies the opening in the oxide layer where the device will be.

Then you do the N+implant (or P+) . You can see that N+ is alwasy bigger then Active - this is to make sure the whole active area gets it implant in case of misalignment.

Usually before the N+ you deposit the poly layer (for creating the channel)

I recommend to read any book about CMOS design - there are 100 pages at the beginning describing the technology (in general terms but it is covering your questions)
 

    020170

    points: 2
    Helpful Answer Positive Rating

Hughes

Advanced Member level 3
Joined
Jun 10, 2003
Messages
717
Helped
113
Reputation
226
Reaction score
25
Trophy points
1,298
Activity points
5,986
We need ACTIVE and N+ Implant/P+ Implant masks. The ACTIVE area enclosed by N+ implant will be n-ACTIVE. But some one prefers to use N-ACTIVE and P-ACTIVE even though N+ Implant and P+ Implant are drawn. N-ACTIVE and P-ACTIVE will be merged to form a single mask --- ACTIVE.
 

020170

Full Member level 4
Joined
Jan 31, 2005
Messages
231
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,298
Activity points
2,225
Re: what is difference between N - active and N + implantati

ok. I agree that I cannot explain which point I have wondered.

I wonder why we have to use N+ implantation layer.

in MAGIC, or simple layout tool, we do not have to use n+ implantation layer

but in practical CMOS process, we have to use it.

why?
 

Hughes

Advanced Member level 3
Joined
Jun 10, 2003
Messages
717
Helped
113
Reputation
226
Reaction score
25
Trophy points
1,298
Activity points
5,986
We always need N+ implant mask. However, sometimes we don't draw N+ implant layer, it can be generated by tools.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top