High k gate stack on III-V compound semiconductors

Abstract

A method of forming a high k gate stack (dielectric constant of greater than that of silicon dioxide) on a surface of a III-V compound semiconductor, such GaAs, is provided. The method includes subjecting a III-V compound semiconductor material to a precleaning process which removes native oxides from a surface of the III-V compound semiconductor material; forming a semiconductor, e.g., amorphous Si, layer in-situ on the cleaned surface of the III-V compound semiconductor material; and forming a dielectric material having a dielectric constant that is greater than silicon dioxide on the semiconducting layer. In some embodiments, the semiconducting layer is partially or completely converted into a layer including at least a surface layer that is comprised of AO_xN_y prior to forming the dielectric material. In accordance with the present invention, A is a semiconducting material, preferably Si, x is 0 to 1, y is 0 to 1 and x and y are both not zero.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a semiconductor structure, and more particularly to a semiconductor structure including a dielectric material having a dielectric constant of greater than that of silicon dioxide located on a passivated surface of a III-V compound semiconductor in which the passivated surface has electrical properties that are sufficient for high-performance field effect transistor (FET) applications. The present invention also provides a method of fabricating such a semiconductor structure. BACKGROUND OF THE INVENTION [0002] In semiconductor technology, an elemental semiconductor material such as, for example, Si or Ge, is typically used as a substrate in which one or more semiconductor devices including, but not limited to, FETs and capacitors, are formed. Of the various elemental semiconductor materials, Si is the elemental semiconductor of choice due to process and performance benefits that are achieved using such an elemental semico...

AI Technical Summary

Benefits of technology

[0012] The present invention provides a method in which a high k dielectric material having a dielectric constant of greater than that of silicon dioxide can be formed on a surface of a III-V compound semiconductor material with electrical properties sufficient for high-performance FET applications wherein the interface between the high k dielectric material and the III-V compound semiconductor material is of good quality, resulting in a low interface state density (on the order of about 1012 cm−2

Problems solved by technology

One major disadvantage of a GaAs semiconductor material (as well as the other III-V compound semiconductors) is the lack of a natural oxide.

This feature hinders the development of standard metal oxide semiconductor (MOS) devices that require the ability to form a surface dielectric.

Moreover, when a dielectric material having a dielectric constant that is greater than silicon dioxide (k greater than 4.0) is deposited on a GaAs semiconductor material that has an unpassivated surface, the interface between the high k dielectric and the GaAs semiconductor material is typically poor, resulting in a high interface state density (on the order of about 1013 cm−2 eV−1 or greater).

Because of such a high interface state density, the electrical properties of the dielectric are insufficient f

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