CN-121992342-A - High-phase-purity Ce-doped iron garnet magneto-optical film and preparation method thereof

Abstract

The invention belongs to the field of magneto-optical film materials, and particularly relates to a high-phase-purity Ce-doped iron garnet magneto-optical film and a preparation method thereof. According to the method, a layer of YIG film with the thickness of 50-60 nm is deposited on a silicon-based substrate as a seed layer through a film preparation process, then an amorphous Ce (radio frequency identification) film with the thickness of 10-15 nm is deposited on the YIG film, an amorphous YIG film with the thickness of 1-2 nm is continuously deposited on the YIG film, then the two layers of amorphous films are integrally annealed and crystallized, and finally the magneto-optical material film with the required thickness can be obtained through the processes of circulating the deposition of the two layers of amorphous films and integrally annealing and crystallizing. The method uses the multi-deposition annealing magneto-optical film material, improves the phase purity of the Ce: RIG film and the Ce 3+ content in the film, has lower thermal budget compared with high-temperature deposition, can effectively avoid the oxidation of the substrate, solves the problems of silicon-based polycrystalline magneto-optical film precipitate and element valence state, and has great significance for preparing the Ce: RIG film with high phase purity.

Inventors

• BI LEI
• JI XINRAN
• ZHANG TIANCHI
• REN ZHENYUAN
• QIN JUN
• DENG LONGJIANG

Assignees

• 电子科技大学

Dates

Publication Date

20260508

Application Date

20260302

Claims (5)

1. 1. The preparation method of the high-phase-purity Ce-doped iron garnet magneto-optical film is characterized by comprising the following specific steps of: Step 1, depositing 50-60 nm amorphous YIG film layers on a silicon-based substrate through a film deposition process, and crystallizing the amorphous YIG film layers through annealing; step 2, depositing an amorphous Ce:RIG film with the thickness of 10-15 nm on the crystallized YIG film in the step 1 through a film deposition process; Step 3, depositing an amorphous YIG film layer with the thickness of 1-2 nm on the surface of the RIG film through a film deposition process, and crystallizing the deposited two amorphous films through an annealing mode; and 4, repeating the step 2 and the step 3 to prepare the pure-phase polycrystalline Ce: RIG film with the required thickness.
2. 2. The method for preparing a high-phase-purity Ce-doped iron garnet magneto-optical film according to claim 1, wherein the film deposition process in the steps 1-3 is magnetron sputtering or pulsed laser deposition.
3. 3. The method for preparing a high-phase-purity Ce-doped iron garnet magneto optical film according to claim 1, wherein the annealing mode in the step 1 and the step 3 is rapid thermal annealing or laser annealing.
4. 4. The method for preparing a high-phase-purity Ce-doped iron garnet magneto-optical film according to claim 1, wherein the step 2 is to deposit an amorphous Ce/RIG film with a thickness of 10 nm a, and the step 3 is to deposit an amorphous YIG film layer with a thickness of 2 nm a, and the total number of rounds is five, and the overall thickness is 60 nm.
5. 5. A high-phase-purity Ce-doped iron garnet magneto-optical film, which is prepared by the method as set forth in any one of claims 1 to 3.

Description

High-phase-purity Ce-doped iron garnet magneto-optical film and preparation method thereof Technical Field The invention belongs to the field of magneto-optical film materials, and particularly relates to a high-phase-purity Ce-doped iron garnet magneto-optical film and a preparation method thereof. Background Silicon-based optoelectronic technology has evolved rapidly in recent years, most active devices can achieve silicon-based integration, but photonic devices based on the non-reciprocal principle, such as optical circulators and optical isolators, remain bulky discrete devices. The magneto-optical film is a key material applicable to silicon-based integrated nonreciprocal devices, so that development of a preparation method of a high-quality magneto-optical film is an important technical problem. Currently, the mode of realizing silicon-based integration of a magneto-optical film mainly comprises two modes of bonding and direct deposition. The direct bonding and the auxiliary bonding can realize silicon-based heterogeneous integration of the epitaxial magneto-optical film, the direct bonding needs to activate the surface of the magneto-optical film and the surface of the silicon-based substrate through plasma, then the two surfaces are contacted, and the two surfaces are firmly combined in a vacuum environment in a high-temperature pressurizing mode, but the surface plasma activation process damages the surface of the magneto-optical film, so that the surface roughness of the film is improved, the transmission loss of the film material is increased, and the magneto-optical effect is weakened. In addition, current bonding techniques rely on expensive wafer bonding equipment and garnet substrate materials are difficult to remove, resulting in limited device structures, large volumes, and high costs. For direct deposition, although wafer-level large-area silicon-based integration of the magneto-optical film can be achieved by magnetron sputtering or the like, the magneto-optical material film exists in a polycrystalline form on a silicon-based substrate. A large number of defects exist in a crystal lattice of the polycrystalline material, particularly a Ce doped silicon-based iron garnet (Ce: RIG) polycrystalline film, and because of low solid solubility of Ce element, a large number of CeO 2 educts exist in the film after normal-temperature deposition annealing, so that the Ce: RIG film with high phase purity is difficult to prepare. In addition, the content of Ce 3+ in the film is low, and most of Ce ions exist in the film in the form of Ce 4+. In the Ce: RIG film, ce 3+ is the main source of Faraday rotation, while the contribution of Ce 4+ to Faraday rotation is very small, so that CeO 2 is precipitated to reduce Faraday rotation of the film. In addition, valence imbalance induced by Ce 4+ induces Fe 2+ ions to form, so that the film loss of the magneto-optical material is further increased. Therefore, in order to further improve the Faraday rotation of the Ce-doped garnet film and reduce the material loss, a deposition process capable of preparing a high-phase-purity polycrystalline Ce: RIG film is urgently needed. Disclosure of Invention Aiming at the problems or the defects, the invention provides a Ce-doped iron garnet magneto-optical film with high phase purity and a preparation method thereof, and aims to solve the problems that the existing Ce-RIG magneto-optical film material is easy to oxidize and separate out CeO 2 second phase and the content of Ce 3+ is low. According to the method, a thin non-spinel film is deposited on the surface of a silicon-based substrate in a magnetron sputtering mode, and the thin magneto-optical film is crystallized in a rapid thermal annealing mode or a laser annealing mode. Because YIG seed layer has better template effect to magneto-optical film of 10-15 nm, in this thickness range, polycrystal Ce: RIG film magneto-optical film material has high phase purity, so after depositing 10-15 nm thick Ce: RIG film, 1-2 nm thick YIG film is deposited to serve as new seed layer, after annealing to make it crystallized, ce: RIG and YIG are deposited on YIG layer, thus preparing pure phase polycrystal Ce: RIG film. Compared with one-time deposition annealing, the film prepared by adopting the process of multiple deposition annealing has higher phase purity and higher Ce 3+ content in the film, so that the problems of CeO 2 precipitation and low Ce 3+ content in the film of one-time deposition annealing can be effectively avoided by adopting the method of multiple deposition film annealing. A preparation method of a high-phase-purity Ce-doped iron garnet magneto-optical film comprises the following specific steps: And 1, depositing 50-60 nm amorphous YIG film layers on a silicon-based substrate through a film deposition process, and crystallizing the amorphous YIG film layers through annealing to serve as seed layers of Ce-RIG films. And 2, depositing an amorphous Ce: RIG f