I have completed Integrated Btech MBA course . Am I eligible for the Ph.D course or not ?

Yes definitely you can do Phd after B.Tech+MBA dual degree.

Top Ph.D colleges Of India are given below :
Amity University
Block - J 2, Ground Floor,
Sector - 125, Noida - 201 303, U. P., India. + 91 - 0120 - 244 5252/ 471 3600

Anna University
Sardar Pa Road, Guindy, Chennai - 600 025, Chennai, Tamil Nadu, India.

Annamalai University
Annamalai Nagar - 608 002, Tamil Nadu, India.

Banaras Hindu University or B. H. U.
Varanasi - 221 005, U. P., India.

Jamia Millia Islamia University or J. M. I. U.
Jamia Nagar, New Delhi - 110 025, India.

Punjab University or P. U., Chandigarh
Sector - 14, Chandigarh - 160 022, India.

University of Calcutta or C. U.
Senate House, 87 / 1 College Street, Kolkata - 700 073, West Bengal, India.

University of Delhi or D. U.
Delhi - 110 007, India.

University of Mumbai or M. U.
M. G. Road, Fort, Mumbai - 400 032, Maharashtra, India.

University of Pune
Ganeshkhind, Pune - 411 007, Maharashtra, India.