Process for depositing electrode with high effective work function

摘要

According to some embodiments, an electrode have a high effective work function is formed. The electrode may be the gate electrode of a transistor and may be formed on a high-k gate dielectric by depositing a first layer of conductive material, exposing that first layer to a hydrogen-containing gas, and depositing a second layer of conductive material over the first layer. The first layer may be deposited using a non-plasma process in which the substrate is not exposed to plasma or plasma-generated radicals. The hydrogen-containing gas to which the first layer is exposed may include an excited hydrogen species, which may be part of a hydrogen-containing plasma, and may be hydrogen-containing radicals. The first layer may also be exposed to oxygen before depositing the second layer. The work function of the gate electrode in the gate stack may be about 5 eV or higher in some embodiments.

主权项

1. A process for semiconductor processing, comprising:
forming a gate electrode comprising a first and a second layer over a substrate, wherein forming the gate electrode comprises: providing the substrate in a reaction chamber, the substrate comprising a gate dielectric; depositing the first layer comprising a transition metal compound on the gate dielectric, wherein depositing the first layer is performed without exposing the substrate to plasma or plasma-generated radicals; increasing a work function of the gate electrode by 0.1 eV to 0.5 eV, wherein increasing the work function comprises: exposing the first layer to hydrogen-containing species, wherein exposing the first layer to the hydrogen-containing species comprises: flowing gas into the reaction chamber, the gas selected from the group consisting of: hydrogen-containing gas, and hydrogen-containing gas with at least one inert carrier gas, and forming an in-situ plasma inside the reaction chamber with the gas, thereby exposing the first layer to the in-situ plasma; or flowing gas into a remote plasma generator to form a remote plasma, the gas selected from the group consisting of: hydrogen-containing gas, and hydrogen-containing gas with at least one inert carrier gas, and flowing the remote plasma into the reaction chamber, thereby exposing the first layer to the remote plasma; and subsequently depositing the second layer comprising a transition metal compound, wherein the gate electrode and the gate dielectric constitute a gate stack, wherein a peak-to-peak voltage for generating the in-situ plasma or the remote plasma is 110 V or higher, and wherein, between depositing the first layer and subsequently depositing the second layer, oxygen plasma is not flowed into the reaction chamber loaded with the substrate and oxygen gas is not flowed into the reaction chamber loaded with the substrate.