Thank you so much Scottieman and Humungus
Now I got to know why SDE is preffered after Ldd. That's cool. Thank you Scottieman for the enlightening words.
Yes Humugus , I saw from somewhere which I forgot(most probably the VLSi book by Prof Stanley Wolf) mentioning the implant ideal profile is a box shape. Since it is real world we are living in, we tend to have some sort of Gaussian profile.
All right, I will find from the website ....
Thank you Scottieman and Humungus and Sky High for always taking the time to post back with excellent ideas
Wish you all success
jason