I am planning on applying to colleges for pursuing an MS degree. I would like to know the scope of semiconductor device modelling, both in terms of jobs as well as research. I also wish to know about any current trends, popular subfields in semiconductor device modelling.
First off, that is a very specialized field with probably not that many jobs globally. It's almost as specialized as, say, writing video chip graphics drivers.
However, there are related fields which are very active at present, most notably in 2D physics eg graphene, molybdenum disulfide, topological conductors semiconductors insulators etc with an eye to future electonics devices ranging from transistor related, to sensors.