ANOMALOUS NARROW WIDTHEFFECTIN NMOS AND PMOS SURFACECHANNEL TRANSISTORSUSINGSHALLOW TRENCH ISOLATION

NMOS surface-channel transistors using shallow trench isolation (STI) isknowntoshow reverse narrow widtheffect (RNWE)suchthatthe threshold voltage becomes smaller whenthechannel width decreases. We found that byusing aphosphorus deepS/Dimplant inaddition toanarsenic deepS/D implant, thethreshold voltage first becomes larger whenthechannel widthdecreases andthenlater becomessmaller whenthechannel widthfurther decreases forNMOS transistors withverysmall gate lengths. We attribute suchananomalous narrow width effect toanenhancement ofTEDduetoSiinterstitials generated by thephosphorus implant. PMOS transistors showupamuchstronger anomalous narrow widtheffect compared toNMOS transistors. We attribute such ananomalous narrowwidth effect toan enhancement ofphosphorus andarsenic TEDduetoSi interstitials generated bythedeep boron S/Dimplant.