Silicon molecular beam epitaxy

Recent results in the field of silicon molecular beam epitaxy (SiMBE) are reviewed. Emphasis is put on the possibility of doping‐profile engineering, as in delta‐doped layers. Heteroepitaxy of Si1 −xGex on Si is discussed in detail. Due to the band‐gap narrowing in the Si1 −xGex several improved devices can be designed, such as heterojunction bipolar transistors and modulation‐doped structures which show potential for improved field‐effect transistors. An exciting area of research involves superlattices consisting of repetitions of layers of Si and Ge, each with a thickness of only a few atomic layers. Review: The thickness of semiconductor layers in superlattices is constantly being reduced due to the quest for miniaturization of electronic components. Using silicon molecular beam epitaxy (Si‐MBE), thin Si or SiGe alloy layers can be epitaxially grown (see Figure) with close control of the dopant profiles of the materials, enabling the production of improved heterojunction bipolar transistors and field effect transistors.