Hi Navadeep,

Only if you are pursuing your final year(i.e 4th year) in BSc(Research)/BS programme or if you have graduated with such degree you are eligible to write GATE exam.You can now pursue MSc and very well appear for GATE exam and do your MTech degree.To pursue MSc in IIT's you may write IIT JAM exam.

To know more about this exam, participating institutes, various course intake and the admission procedure do visit the link below

https://university.careers360.com/articles/jam-programmes

All the best!!