Epitaxial thin film used for high-dielectric constant gate dielectric and preparation method thereof

Abstract

The invention relates to a material used for a high-dielectric constant (high-k) gate dielectric in a new generation integrated circuit field-effect tube and a preparation method thereof. The epitaxial thin film material used for the high-dielectric constant gate dielectric is a single high-oriented epitaxial thin film on an Si(001) underlay; the thin film is a single-crystalline state hafnium-lanthanum composite oxide La2Hf2O7 with a pyrochlore phase structure; and the crystallographic orientation relationship between the thin film and the Si(001) underlay is La2Hf2O7(001)//Si(001). In the preparation method of the epitaxial thin film, a hafnium-lanthanum composite oxide (La2Hf2O7) ceramic target material with a pyrochlore phase is obtained by a reactive sintering method, and then the single high-oriented epitaxial thin film with smooth surface and even interface is deposited on the Si(001) underlay under the condition of ultrahigh vacuum by adopting a laser molecular beam deposition technology. The epitaxial thin film material is applied to the gate dielectric of the new generation integrated circuit field-effect tube.

Description

technical field [0001] The invention relates to a high dielectric constant (high-k) grid dielectric material used in a new generation of integrated circuit field effect transistor and a preparation method thereof. By obtaining La with high thermal stability 2 f 2 o 7 Ceramic targets, growth temperature is adjusted, and high-k gate dielectric replacement materials with good chemical stability and electrical properties are grown in the laser pulse deposition system. Background technique [0002] With the rapid development of integrated circuits, the size of CMOS devices continues to decrease, the quantum tunneling effect begins to become significant, and the leakage current of the silicon dioxide gate dielectric increases greatly; there is a concentration of impurities between the gate, silicon dioxide and silicon substrate Gradient, the thinning of the gate thickness causes the diffusion of impurities to be more serious [1, 2]. In order to ensure that the capacity of the ...

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Problems solved by technology

[0005] 1. The oxide and Si substrate will inevitably form an intermediate transition layer at the interface due to the problem of oxygen diffusion, which usually greatly reduces the effective dielectric constant of the gate dielectric layer

Rare earth metals are also easy to form silicides with Si, making high-k oxides unable to be used as gate dielectric layers in field effect transistors

[0006] 2. Although rare earth oxides generally have higher dielectric constants and conduction band offsets than hafnium oxides, their applications are limited due to their low crystallization problems

[0007] 3. Epitaxial thin films have attracted attention due to their smaller bulk defects, however, usually HfO 2 The lattice mismatch between the material and the semiconductor substrate is large, and the obtained epitaxial film has dislocations such as grain boundaries and kinks, resulting in excessive leakage current

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