Nitride films with improved etch selectivity for 3D NAND integration

Abstract

A method of depositing a nitride layer on an oxide layer to form an oxide-nitride stack is provided. The method includes: supplying an inert gas into a plasma enhanced chemical vapor deposition (PECVD) reactor that supports a substrate having the oxide layer. Then, power is supplied to an electrode of the PECVD reactor, the power being configured to excite a plasma. Next, a reactant gas is flowed into the PECVD reactor. The reactant gas includes a first volume percentage of ammonia (NH3), a second volume percentage of nitrogen (N2), a third volume percentage of silane (SiH4), and a fourth volume percentage of an oxidant. The fourth volume percentage of the oxidant is at least 0.5% by volume and less than about 8% by volume. Then, the reactant gas is continuously flowed into the PECVD reactor until it is determined that the nitride layer has reached a target thickness on the oxide layer.

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