Sorry, you are not eligible to apply for Ph.D after completing your Master of Computer Application (MCA). MCA degree is a technical degree and is equivalent to B.E/B.Tech degree. You need to complete M.Tech degree to be eligible for Ph.D.
You can appear for GATE Exam to pursue M.Tech. Graduate Aptitude Test in Engineering (GATE) is an all India examination administered and conducted jointly by the Indian Institute of Science (IISc) and seven Indian Institutes of Technology (IITs) on behalf of the National Coordination Board - GATE, Department of Higher Education, Ministry of Human Resource Development (MHRD), Government of India, for admission to Post Graduation/PhD courses in Engineering and Architecture.
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