Vertically standing single-walled carbon nanotube (SSWCNT)-embedded transistors have been demonstrated for a flash memory application. The performance of the SSWCNT device was compared with a lying SWCNT (LSWCNT) device to verify the directional effect of immobilized SWCNTs. The SSWCNT device shows a better program/erase transient and a threefold enhanced retention characteristics over the LSWCNT device due to the high coupling ratio and the defect immunity based on the isolated distribution and vertical directionality nature of the SSWCNT. (c) 2007 American Institute of Physics.