The potential for cost and space reduction is also a huge advantage. Fabrication of a device using thin film techniques often requires very little material. This means that the process can be not only more cost-effective, but the device itself can be smaller and lighter. This kind of space reduction is the reason for the transition from thermionic vacuum tubes to semiconductors, and it is still an influential factor today. In comparison to a bulk material, the thin film form of that material will often possess quite different properties. A lot of the time, these properties will show an improvement from those of the bulk material, and it is the ability to alter the surface properties of the substrate which is very advantageous.