what is better if I have to go for a Research based job,that should I go for it after B.tech ,after M.tech or after PhD?? And should I go Abroad for Mtech or PhD (because I think India has less opportunity in research)?
Well see if you want then you can go research after bachelors fom basic science or from engineering. You can continue your research in your doctoral work and then can do something more in post doctoral work. It totally depends on you and yes India do has less research opportunities and that is why you can go abroad for your research.
I hope my answer helps.
All the best.