Method for epitaxially growing strontium titanate (STO) thin film on gallium arsenide (GaAs) substrate

Abstract

The invention relates to a method for epitaxially growing a strontium titanate (STO) thin film on a gallium arsenide (GaAs) substrate. The method comprises the following steps: 1. treating the surface of the GaAs substrate to form a flat atomically clean surface with Ga atoms as the final surface; 2. sending the GaAs substrate treated in the step 1 and an STO target to the vacuum chamber of laser molecular beam epitaxy (MBE) equipment and immobilizing the GaAs substrate and the STO target in the vacuum chamber; 3. heating the GaAs substrate immobilized in the step 2 to the temperature between 550-600; and 4. evaporating the STO target immobilized in the step 2 with laser beams to ensure the STO to be deposited on the GaAs substrate, using reflection high energy electron diffraction to monitor the growth process of the thin film in the deposition process and obtaining the STO epitaxial thin film when typical STO diffraction fringes appear on the diffraction patterns. The method has the following beneficial effect: the surface of the GaAs substrate is treated to form the flat atomically clean surface with Ga atoms as the final surface, thus overcoming the difficulty in growing the dielectric oxide thin film on the GaAs substrate binary compound.

Description

technical field [0001] The invention belongs to the technical field of materials, and relates to the epitaxial growth of strontium titanate (SrTiO) on a gallium arsenide (GaAs) substrate. 3 , referred to as STO) dielectric film method. Background technique [0002] GaAs semiconductor material is a typical direct bandgap wide bandgap semiconductor material, the bandgap width at room temperature is 3.37 electron volts (ev), and the electron mobility is as high as 8500cm 2 / V*s (square centimeters per volt second). In recent years, people have been hoping to integrate dielectric functional oxide STO thin film materials with gallium arsenide materials to form GaAs-based metal oxide semiconductor field effect transistors (MOSFETs). Using the electro-optic and dielectric tunable properties of STO as a dielectric material and the high mobility and direct bandgap properties of GaAs to develop high-frequency semiconductor devices with electro-optical coupling, optical waveguide and...

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Problems solved by technology

At the same time, Liang et al. from Freescale successfully epitaxial the oxide dielectric SrTiO with the MBE (Molecular Beam Epitaxy) crystal growth technology equipped with metal Ti (titanium) and Sr (strontium) sources. 3 , but this method is very complicated, requires an independent noble metal source, and has a high growth temperature. Although epitaxially grown STO can be obtained, the interfacial diffusion destroys the semiconductor properties that GaAs should have

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