1) is mtech better(wide scope) or mba after btech in ECE ,2) best colleges for mba by which i can get easily placement?

see, the conflict between MTech and MBA should be resolved by evaluating ones own interest. if you feel an inclination to technical domain, go for MTech else MBA. one more thing, MBA might not be in line with your past curriculum, i mean ECE. best ones for MBA in india are IIMs, XLRI, ISB, FMS, IIT