SONOS, short for "silicon–oxide–nitride–oxide–silicon", more precisely, "#polycrystallineSilicon"—"#siliconDioxide"—"#siliconNitride"—"silicon dioxide"—"silicon", is a #crossSectional structure of #MOSFET (metal–oxide–semiconductor field-effect #transistor), realized by P.C.Y. Chen of #FairchildCameraAndInstrument in 1977. This structure is often used for #nonvolatileMemories, such as #EEPROM and #flashMemories. It is sometimes used for #TFTLCD #displays.