Hello Gowtham,

A very good question. B.Tech is an Undergraduate course while M.Tech is Post Graduation Course. Lot of students after completing B.Tech apply for jobs. While some who want to go in Teaching, Research and Development field they go for Higher studies like M.Tech. For M.Tech students prefer institutes like IIT's, IISC, etc on the basis of their score in GATE Examination. So once they do M.Tech then they will be having more and in depth knowledge of particular subject than a normal B.Tech student due to which they get good package placements. Some are selected for research purposes while some get in government services.

I hope you understood it !