Method for preparing thin film material of binary rare earth compounds

Abstract

This invention provides a preparation for binary rare earth compound thin films. A low-energy double ion beam deposition apparatus is adopted for its function of mass separation and characteristics of energetic ion deposition, and rare earth chlorides of which purity is not highly required serve as raw materials for I beam of Bonus solid ion source to give out an isotopic pure low-energy rare earth ion beam, which with another isotopic pure low-energy ion from II beam of Bonus gaseous ion source is deposited alternately in ultravacuum cultivation room. By exactly controlling the energy of the isotopic pure low-energy ions, beam shape, beam flux, beam proportion and growing temperature, deposition and low-temperature epitaxy of binary rare earth compounds which have high temperatures and are difficult to purify and easy to oxidized can be realized. A wide variety of rare earth thin films can be prepared according to this invention and the technique is convenient to modulate and optimized, which is economical to manufacture rare earth thin films used in semiconductor technology and some other fields.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing and growing binary rare earth compound thin film materials using mass-separated low-energy dual ion beam deposition equipment. Background technique [0002] Binary rare earth compound thin films are an important part of new functional materials, and are currently widely used in various fields. In particular, with the tremendous development of electronic information technology in recent years, the development and application of such materials in microelectronics, optoelectronics and magnetoelectronics in the field of semiconductors has attracted more and more attention. For example, some rare earth oxide films with high dielectric constants (such as cerium oxide (CeO 2 ), yttrium oxide (Y 2 o 3 ), etc.) are likely to replace silicon dioxide (SiO2) commonly used in microelectronics technology 2 ), become a new type of gate dielectric insulating mat...

AI Technical Summary

Problems solved by technology

Although as early as 1995, people began to use low-energy double ion beam deposition method to prepare rare earth thin films, such as cerium oxide (CeO 2 ) thin films, but so far this method has not really become practical and widely promoted. The reasons for the analysis mainly include the following aspects: 1) Most of the original low-energy dual ion beam deposition methods use Freeman (Freeman) type solids Ion source, utilizes rare earth oxide as the raw material that produces rare earth element ion, and produces the working atmosphere of rare earth element chloride with the chlorination reaction in carbon tetrachloride gas to produce rare earth element ion, but because under the working pressure of ion source (10 -3 Pa to 10 -2 Pa), the amount of the carbon tetrachloride reaction gas that feeds is limited, and the rare earth oxide with high melting point and good stability is also easy to operate at a higher Freeman type ion source operating temperature (sometimes more than 800 ° C). Sintering and hardening, so only a small amount of rare earth chloride can be generated. The working atmosphere enters the arc chamber of the ion source for ionization, and the generated rare earth element ion beam current is small, and the film deposition efficiency is low; 2) The original low-energy dual ion beam deposition method , there is also an attempt to directly use rare earth chlorides as the working substance of the Freeman-type ion source, but the initial temperature of the Freeman-type ion source is relatively high, and the filament will be quickly sputtered by the ions during work. As a result, the temperature of the ion source is also reduced, and the working temperature of the ion source is unstable, which makes it difficult for the rare earth chloride as the working material of the ion source to volatilize stably to meet the working needs of the ion source. The rare earth element ions produced The beam current is large and small, which is difficult to control; 3) The original low-energy dual ion beam deposition method, the preparation of binary rare earth compound thin films mostly adopts the double beam co-deposition method of rare earth element ions and compound material ions to prepare and grow. The coincidence degree of the beam spots of the two ion beams deflected and converged on the substrate is not very good, which affects the uniformity of film formation. In addition, the dose and ratio of the two ions co-deposited by the two beams can only be determined by deceleration. It is determined by the size of the ion beam current, and the dose and ratio of deposited ions required for material growth cannot be accurately controlled, resulting in poor repeatability of the grown film, and is not conducive to further optimization of the growth process.

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