An apparatus and method for depositing a tunneling oxide layer between two
conducting layers utilizing a low pressure, low temperature chemical vapor
depostion (LPCVD) process is disclosed wherein tetraethylorthosilicate
(TEOS) is preferably used. As applied to an electrically erasable
programmable read only memory (EEPROM) device having polysilicon layers,
the apparatus is constructed by forming a first layer of polysilicon,
patterned as desired. A layer of silicon dioxide is then deposited by
decomposition of TEOS to form the tunneling oxide to a predetermined
thickness. If enhanced emission structures are desired, a layer of
relatively thin tunneling oxide may be grown on the first layer of
polysilicon. The oxide layer is then annealed and densified, preferably
using steam and an inert gas at a specific temperature. A second layer of
polysilicon is then formed on top of the tunneling oxide.