Nearly all modern IC chips are metal–oxide–semiconductor (MOS) integrated circuits, built from MOSFETs (metal–oxide–silicon field-effect transistors). The MOSFET (also known as the MOS transistor), which was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959, made it possible to build high-density integrated circuits. Atalla first proposed the concept of the MOS integrated circuit (MOS IC) chip in 1960, noting that the MOSFET's ease of fabrication made it useful for integrated circuits. In contrast to bipolar transistors which required a number of steps for the p–n junction isolation of transistors on a chip, MOSFETs required no such steps but could be easily isolated from each other. Its advantage for integrated circuits was re-iterated by Dawon Kahng in 1961. The list of IEEE milestones includes the first integrated circuit by Kilby in 1958, Hoerni's planar process and Noyce's planar IC in 1959, and the MOSFET by Atalla and Kahng in 1959.