IIT

A software engineer is a person who applies the principles of software engineering to the design, development, maintenance, testing, and evaluation of the software and systems that make computers or anything containing software work.
You have following options to become a software engineer:
(a) B.Tech CS/ IT
(b) BCA-MCA,
(c) B.Sc-M.Sc CS/IT.
(d) Diploma in Computer Science from a polytechnics
(e) Computer courses
There is only subtle difference between CSE, IT and SE. IT Industry accepts all three to start career as Software Developer. Majority of institutes offer o work as software engineer. B.Tech CSE and it the most accepted degree in IT industry to work as a Software engineer. Let me explain you difference between CS, IT and SE.
Computer science the study of automating algorithmic processes that scale. A computer scientist specializes in the theory of computation and the design of computational systems. B.Tech IT degree has a major focus on computers and technology, it differs from a Computer Science degree in that students are also expected to study management and information science, and there are reduced requirements for mathematics and theory of computation. Software Engineering (SE) deals with building and maintaining software systems. It is more applied than Computer Science, placing greater emphasis on the entire software development process, from idea to final product. It is also more disciplined than Computer Science, applying more systematic practices to help ensure that products are reliable and safe.

To become a physics professor in IIT and any other TIER-1 colleges like IITs, 5NITs, DTU, BITS, and IIITH is not an easy task.
You need to have a PhD from country's most reputed college like like IISc Bangalore, IIT-Delhi, Bombay Kanpur. It's all about decorating your profile by doing some really good research papers. If you manage to prove your worth in your research area, and it impresses your Head of the Department; you can get a job as guest faculty. And you get paid for this. Actually, there's a high possibility of you getting chosen as an Asst. Prof of the same IIT from where you've applied for your Doctorate.
WHAT TO KEEP IN MIND:
1- You should be a pass-out from TIER1 colleges which were mentioned above.
2- Your profile is minutely checked, UG College, PG college and your CGPA should be &get;8
3- you need to impress the faculty and the H.O.D of the colleges where you want to teach even if you can't 'Teach' well, it doesn't matter unless you're highly qualified.