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)
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.