M.Tech

Yes, you are eligible for Ph.D after completing your M.Tech. Please check for your eligibility from the criteria mentioned below:
Eligibility for Ph.D. in Physics:
1) M.Phil. Degree or M.Sc. In Physics or Material Science
2) A minimum aggregate score of 60% or equivalent CGPA (relaxed to 55% or equivalent CGPA for SC/ST) at the level of post-graduation
3) Qualification of any of the following national level tests in Physics in the last 2 years from applying to the course:
4) CSIR/UGC-JRF or CSIR/UGC LS with rank less than or equal to 200
5) JEST/GATE with rank less than or equal to 300. Selection is based on the shortlisted candidates performance in the round of personal interview. Regards.

Dear Siddharth!
It depends upon your interest and your future goals. You should to go for B.Tech + M.Tech if you want to continue your specializations. That's makes you much expertise in that particular feild. And you know very well that core companies need the one who has done his Masters in the continuation of specializations. BUT you should to go for B.Tech+MBA if you also posses some managerial skills or you want to have to combination of engineering and managerial skills. That's a very promising career also. So it's all upto you. Both the courses re in demand and will grow at the equal pace. Italian all ll depends upon your futuristic planning. Hope this helps. Upvote the answer if you feel satisfied. Ask any query at anytime. Good Luck.