Method for forming high dielectric constant metal oxides

A method for forming a semiconductor structure, the method comprising the steps of:

• providing a semiconductor substrate having a surface;
• forming an oxidation barrier layer over the surface of the semiconductor substrate by exposing the semiconductor substrate to a nitrogen environment, the oxidation barrier layer having a dielectric constant between 3.9 and 8.0;
• forming a metal oxide layer over the oxidation barrier layer, the metal oxide layer having a dielectric constant above 7.8;
• forming a metallic gate electrode overlying the metal oxide layer;
• and
• forming source and drain electrodes within the semiconductor substrate and self-aligned to the metallic gate electrode wherein the gate electrode controls current flow between source and drain electrodes using the oxidation barrier layer and the metal oxide layer as a composite gate dielectric layer.

A method for forming a semiconductor structure, the method comprising the steps of:

• providing a silicon substrate;
• annealing the silicon substrate in a hydrogen-containing environment to passivate a surface of the silicon substrate;
• forming an oxidation barrier layer over the surface of the silicon substrate by exposing the semiconductor substrate to a nitrogen environment, the oxidation barrier layer having a dielectric constant between 3.9 and 8.0 and being chemically stable in contact to silicon;
• forming a metal oxide layer over the oxidation barrier layer, the metal oxide layer having a dielectric constant above 7.8 and being chemically unstable in contact to silicon;
• forming a metallic gate electrode overlying the metal oxide layer wherein a lower portion of the metallic gate electrode is made of a metal material, a middle portion of the metallic gate electrode is made of polysilicon, and an upper portion of the metallic gate electrode is made of a silicide material;
• and
• forming source and drain electrodes within the silicon substrate and self-aligned to the metallic gate electrode wherein the gate electrode controls current flow between source and drain electrodes using the oxidation barrier layer and the metal oxide layer as a composite gate dielectric layer.