Some colleges including IITs and NITs offer dual degree course in which you can complete B Tech and M Tech in 5 years instead of regular 6 years. In the course first three years will be similar to 4 year B Tech with some additional subjects and on the last 2 years you will be having more like Many Tech students. I would not recommend you to go for it unless you are very much interested in the research because it puts you many limitations compared to just Be Tech and you may later finds that you are more concerned about jobs rather than degree therefore you should go for normal B Tech.