Al2O3-SiO2IGFET integrated circuits

This paper reports on discrete and integrated IGFET´s fabricated using the aluminum oxide-silicon dioxide gate dielectric. Both the fabrication techniques and the electrical performance of the circuits will be discussed. IGFET discrete devices and integrated circuits of the P channel enhancement type are fabricated on 5 ohm-cm, oriented, n-type silicon. Standard processing is employed except for the Al2O3deposition step and the contact window etching procedure. In order to etch the contact windows, the Al2O3is covered by a deposited SiO2layer which serves as a mask during the etching of the Al2O3in hot H2PO4. The mask layer is SiO2is removed during the last step in the contact window etch. A threshold voltage of minus one volt is obtained using 500Å of deposited aluminum oxide over 1000Å of thermally grown silicon dioxide.