Problems in the melt- and vapor growth of silicon for integrated circuits and solar cells

Since the invention of the transistor in 1948 silicon has emerged as the most versatile semiconductor material, and the resulting devices have caused a revolution in the electronics industry. The crystal growth of silicon from the melt is the basis for the nearly perfect crystalline quality needed for the devices. Problems in the melt growth, the elimination of dislocations, and the prevention of the precipitation of point defects are still under study and are discussed. In addition, the growth of thin monocrystalline layers of Si on a monocrystalline substrate has become of great importance. In sharp contrast to this type of approach are the recent activities aimed at obtaining cheap silicon photovoltaic solar cells. Examples of methods based on melt or vapor growth for producing thin, almost monocrystalline layers on a cheap substrate are given. The new discovery that amorphous silicon may be a suitable candidate for this type of cells is discussed.