Hello,
I think btech in biotechnology is a good choice although placements are not like computer science but if you work hard you can take a good placement also. Good college will provide better labs , infrastructure and placement . As you are more concerned on Mtech you should study well in your btech to clear entrance exams. So, if you want to go to only higher studies you can go to average college otherwise for placements you should try a reputed college. Hope this will help you.