There is no one-size-fits-all answer to this question, as it depends on individual circumstances. However, in general, it is possible to switch the area of research in CS going from M.Tech to PhD, although it may be more difficult than if you were starting from scratch. If you have already done some research in your M.Tech program and have a good idea of the direction you want to go in, it may be easier to make the switch. However, if you are starting from scratch, it may be more difficult to make the switch, as you will need to learn a new area of research and build up your expertise. In either case, it is important to consult with your advisor and other experts in the field to get guidance on making the switch.
