Mechatronics engineering is a specialization in B.tech & M.tech both. Also, you can do 5 years B.tech-M.tech dual degree in this course and go for research field also.
IIT only provide M.tech degree in the specialization and NIT, Rourkela gives 5 Years dual degree in this course (Mechanical Engineering and M.tech Mechatronics and automation).

if you want to know know more about Mechatronics engineering, you can go through below link:

http://www.engineering.careers360.com/mechatronics-engineering

Good Luck.