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AssigneeKwangju Institute of Science and Technology
InventorsHyun Sang Hwang, Sang Hun Jeon
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Disclosed is a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant comprising formation of a metal oxide or a metal silicate on a silicon substrate, nitridation to incorporate nitrogen component to said metal oxide and reoxidation of said metal oxide that contains said nitrogen component. In this invention, the nitridation can be performed via heat-treatment of the resulting product, wherein said metal oxide is formed within, in a nitrogen-containing gas atmosphere; performed by plasma treatment by exposing said metal oxide to a nitrogen-containing plasma atmosphere; or performed by ion instillation of nitrogen component to said metal oxide, thereby providing a gate dielectric for use in semiconductor device which is able to remarkably inhibit the increase in effective thickness resulted from a post heat-treatment at high temperature by forming a film of metal oxide such as ZrO2 followed by nitridation and reoxidation.
A method of fabricating gate dielectric for use in semiconductor device comprising the steps of;
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On single crystalline silicon, e.g. chemical oxidation using a liquid: in a nitrogen-containing ambient, e.g. N2O oxidation
On single crystalline silicon, e.g. chemical oxidation using a liquid: with a treatment, e.g. annealing, after the formation of the insulator and…
Characterised by the insulator, e.g. by the gate insulator: the insulator comprising nitrogen, e.g. nitrides, oxynitrides or nitrogen-doped materials
Formation by oxidation, e.g. oxidation of the substrate: of a metallic layer
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The present invention relates to a method of fabricating gate dielectric for use in semiconductor device, and more particularly, to a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant via nitridation.
Thin ZrO2 film, a film that has been spotlighted as a gate dielectric with high dielectric constant for next generation, is reported to enable to have excellent electrical properties via various processing optimizations. However, as is the case with other metal oxides, it becomes inevitable to perform heat treatment for thin film of ZrO2 at a relatively high temperature when using the thin ZrO2 film as a dielectric gate for MOSFET, and this results in the drastic increase in effective thickness due to the growth(increase) in interfacial layer of silicate or silicon oxide which is formed in the interface between silicon substrate and thin film of ZrO2.
The present invention relates to a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant comprising formation of a metal oxide on a silicon substrate, nitridation to incorporate nitrogen component to said metal oxide and reoxidation of said metal oxide that contains said nitrogen component. Examples of said metal oxides include ZrO2, HfO2, La2O3, Al2O3 and Ta2O5, and other metal silicates such as ZrSixOy, HfSixOy, LaSixOy, AlSixOy and TaSixOy can be also used for the same purpose. Further, the nitridation can be performed by heat-treating the resulting product, wherein said metal oxide is formed within, in a nitrogen-containing gas atmosphere; performed by plasma treatment by exposing said metal oxide to a nitrogen-containing plasma atmosphere; or performed by ion implantation of nitrogen component to said metal oxide.
FIG. 1 is a graph that shows the increase in effective thickness for ZrOxNy and ZrO2 films at the time of post-heat-treatment.
FIG. 2 is a graph that shows the decrease in leakage current for ZrOxNy and ZrO2 films at the time of post-heat-treatment.
FIGS. 3a and 3b are cross-sectional images taken by electron microscopy of ZrOxNy and ZrO2 films heat-treated for 5 min at 800° C.
The present invention relates to a method of fabricating gate dielectric for use in semiconductor device having a high dielectric constant comprising formation of a metal oxide on a silicon substrate, nitridation to incorporate nitrogen component to said metal oxide and reoxidation of said metal oxide that contains said nitrogen component. Examples of said metal oxides are ZrO2, HfO2, La2O3, Al2O3 and Ta2O5 and other metal silicate such as ZrSixOy, HfSixOy, LaSixOy, AlSixOy and TaSixOy can be also used.
The nitridation can be performed by heat-treating the resulting product, wherein said metal oxide is formed, in an atmosphere of nitrogen-containing gas atmosphere, performed by plasma treatment by exposing said metal oxide to a nitrogen-containing plasma atmosphere, or performed by ion instillation of nitrogen component to said metal oxide. The nitrogen-containing gas that can be used in the present invention are N2O, NO or NH3, and the heat-treatment is performed for 10 sec-1 hr. The nitrogen-containing plasma that can be used in the present invention is N2 or NH3.
The reoxidation is performed via heat-treatment in an atmosphere of O2, O3 or H2O(g) for 10 sec-1 hr at a temperature ranging from 300° C. to 1000° C.