The monocrystalline form is used in the semiconductor device fabrication since grain boundaries would bring discontinuities and favor imperfections in the microstructure of silicon, such as impurities and crystallographic defects, which can have significant effects on the local electronic properties of the material. On the scale that devices operate on, these imperfections would have a significant impact on the functionality and reliability of the devices. Without the crystalline perfection, it would be virtually impossible to build Very Large-Scale Integration (VLSI) devices (figure below), in which millions (up to billions, circa 2005[2]) of transistor-based circuits, all of which must reliably be working, are combined into a single chip to get e.g. a microprocessor. Therefore, the electronics industry has invested heavily in facilities to produce large single crystals of silicon.