CN101404198B - Diluted magnetic semiconductor material with high Curie temperature and preparation method thereof - Google Patents

Abstract

The invention discloses a diluted magnetic semiconductor material with high Curie temperature and a preparation method thereof; firstly, 4H-SiC with the consistency of 10<16>cm<-3> is used as substrate material and pre-cleaning disposal is carried out; subsequently, Fe ion with the consistency of 5.1% is injected into the substrate material; subsequently, HNH annealing disposal is carried out for the substrate material after the injection of Fe ion is completed; the substrate material is annealed for 5 minutes under the temperature of 300 DEG C under the hydrogen environment, annealed for 5 minutes at the temperature of 700 DEG C under the nitrogen environment and then annealed for 5 minutes at the temperature of 250 DEG C under the hydrogen environment. The gained diluted magnetic semiconductor material has high Curie temperature; furthermore, the preparation process is compatible with the preparation process of the existing integration circuit and has wide application prospect.

Description

Diluted magnetic semiconductor material with high Curie temperature and preparation method thereof

technical field

The invention relates to a preparation method of a semiconductor material, in particular to a dilute magnetic semiconductor material with a high Curie temperature and a preparation method thereof.

Background technique

Diluted magnetic semiconductor materials (DMS) have certain ferromagnetism and are compatible with semiconductor materials, so they have broad application prospects and are widely used in magnetic devices, magneto-optics, magnetoelectronics and other fields. At present, this type of material has been successfully It is used in spin-related devices, such as magnetic memory, spin filter devices, and quantum devices.

Diluted magnetic semiconductor materials in the prior art have a low Curie temperature, which cannot meet the conditions for application at room temperature. In terms of the preparation process of the material, the compatibility with the mature integrated circuit manufacturing process of mass production is relatively low.

Contents of the invention

The object of the present invention is to provide a dilute magnetic semiconductor material with a high Curie temperature and a preparation process compatible with the existing integrated circuit manufacturing process and a preparation method thereof.

The purpose of the present invention is achieved through the following technical solutions:

The dilute magnetic semiconductor material with high Curie temperature of the present invention includes a 4H-SiC substrate, and Fe ions are injected into the 4H-SiC substrate material.

The above-mentioned preparation method of the dilute magnetic semiconductor material with a high Curie temperature of the present invention comprises the steps of:

First, select the 4H-SiC substrate material and perform pre-cleaning treatment;

Then, implanting Fe ions into the 4H-SiC substrate material;

Afterwards, annealing is performed on the substrate material after the Fe ion implantation is completed.

It can be seen from the above-mentioned technical scheme provided by the present invention that the dilute magnetic semiconductor material with high Curie temperature and the preparation method thereof according to the present invention, because Fe ions are injected on the 4H-SiC substrate, after annealing treatment, the obtained The dilute magnetic semiconductor material has a high Curie temperature, and the preparation process is compatible with the existing integrated circuit manufacturing process.

Description of drawings

Fig. 1 is the XRD collection of illustrative plates corresponding to different annealing stages in the specific embodiment of the present invention;

Fig. 2 is a schematic diagram of the relationship between magnetism and temperature of different samples under a 500e magnetic field in a specific embodiment of the present invention;

Fig. 3 is a schematic diagram of a hysteresis loop of Si0.95Fe0.05C in a specific embodiment of the present invention.

Detailed ways

The preferred embodiment of the dilute magnetic semiconductor material with high Curie temperature of the present invention includes a 4H-SiC substrate, and Fe ions are injected into the 4H-SiC substrate material. The concentration of Fe ions may be 5.0-5.2%, such as 5.1%, or other concentrations may be selected. The concentration of the 4H-SiC substrate material can be about 10 ¹⁶ cm ^-3 , and other concentrations can also be selected.

The above-mentioned preparation method of the dilute magnetic semiconductor material with high Curie temperature of the present invention, its preferred embodiment is, comprises the steps:

First, select a suitable concentration of 4H-SiC substrate material and perform pre-cleaning treatment;

Then, implant Fe ions into the 4H-SiC substrate material;

Afterwards, annealing is performed on the substrate material after the Fe ion implantation is completed.

The above-mentioned pre-cleaning treatment can be, first, adopt standard RCA cleaning, then soak in hydrofluoric acid with a concentration of 4-6% for 18-22 seconds, and then soak in hydrofluoric acid with a concentration of 5% for 20 seconds Bell, you can also choose other solutions or concentrations to soak as needed. Then dry it.

The above-mentioned process conditions for implanting Fe ions into the 4H-SiC substrate material can be:

The implantation energy can be 240-260keV, such as 250keV; the implantation quantity can be 3×10 ¹⁶ cm ^-2 to 5×10 ¹⁶ cm ^-2 ; the implantation temperature can be higher, such as greater than or equal to 300°C.

During the process of implanting Fe ions, the substrate material can be tilted by about 7°, such as 6-8°, so as to avoid pipeline defects.

The above-mentioned annealing treatment of the substrate material after Fe ion implantation adopts the HNH annealing process, and the specific HNH annealing process includes:

First anneal at 290-310°C for 4-6 minutes under hydrogen atmosphere, then anneal at 690-710°C for 4-6 minutes under nitrogen atmosphere, and then anneal at 240-260°C for 4-6 minutes under hydrogen atmosphere.

A specific embodiment of the HNH annealing process includes:

First anneal at 300°C for 5 minutes under hydrogen atmosphere, then anneal at 700°C for 5 minutes under nitrogen atmosphere, and then anneal at 250°C for 5 minutes under hydrogen atmosphere.

In the present invention, Fe is used as an impurity to be doped into 4H-SiC to form a (SiFe)C structure. The doping process used is ion implantation, which is compatible with conventional integrated circuit technology. In conjunction with the unique HNH annealing method of the present invention, The Curie temperature of the obtained dilute magnetic semiconductor material can be as high as 320K.

After doping Fe, the material can still maintain the original crystal structure after proper annealing.

As shown in Figure 1, the XRD patterns corresponding to different annealing stages of the sample prepared for the specific embodiment of the present invention, in the figure,

Curve a is the XRD pattern of the sample annealed at 300°C for 5 minutes under a hydrogen atmosphere;

Curve b is the XRD pattern of the sample after annealing at 700°C for 5 minutes under nitrogen atmosphere on the basis of curve a;

Curve c is the XRD pattern of the sample after annealing at 250° C. for 5 minutes under hydrogen atmosphere on the basis of curve b.

It can be seen from the curve a in Figure 1 that after annealing at 300°C for 5 minutes in a hydrogen atmosphere, in addition to the peak corresponding to the substrate SiC, there is also SiFe2 along the (112) crystal direction, which shows that at this time Crystallization of SiFe2 appeared in part of the structure; after annealing at 700°C for 5 minutes under nitrogen atmosphere, it can be seen from curve b that the crystallization degree of the sample has been significantly improved; After annealing at ℃ for 5 minutes, it can be seen from the curve c that the relative strength of SiFe2 is significantly improved, the peak height corresponding to SiFe2 (112) is obviously enhanced, and the direction of (211) is decreasing, and a new peak ( 004), which proves that the HNH annealing step can improve the crystallization degree of Fe-Si.

It can be observed from the illustration in Figure 1 that in addition to the appearance of SiFe2, β-SiC appears, which means that due to the doping of Fe in the SiC material, the original destroyed 4H-SiC structure is recrystallized into β under the action of the HNH annealing process. -SiC.

As shown in FIG. 2 , after the material samples of the specific examples were prepared, the Curie temperature was measured. There were three samples with different Fe concentrations, and the Fe concentrations were 0.025, 0.051, and 0.065, respectively. It can be seen that when the concentration of Fe corresponds to 0.051, the corresponding Curie temperature is 320K.

As shown in Figure 3, the sample containing Fe0.051 was tested at 320K, and it has obviously good magnetic properties, which can reach the level of practical application.

In the present invention, on the 4H-SiC substrate, Fe ions are implanted into the substrate material by ion implantation, and after being treated by a unique HNH annealing method, a dilute magnetic semiconductor material is obtained. When the concentration of Fe is controlled at 5.1%, the corresponding The Curie temperature of the material is 320K, which is higher than room temperature, and has broad application prospects.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims (8)

1. preparation method with dilute magnetic semiconductor material of high-curie temperature, described dilute magnetic semiconductor material with high-curie temperature comprises the 4H-SiC substrate, is marked with the Fe ion in the described 4H-SiC backing material, it is characterized in that, comprises step:

At first, select the 4H-SiC backing material, and carry out pre-clean processes;

Then, in described 4H-SiC backing material, inject the Fe ion;

Afterwards, the backing material that the Fe ion is injected after finishing carries out annealing in process;

Described annealing in process adopts the HNH annealing process, and described HNH annealing process comprises:

At first under hydrogen atmosphere 290～310 ℃ annealing 4～6 minutes, then under nitrogen atmosphere 690～710 ℃ annealing 4～6 minutes, thereupon again under hydrogen atmosphere 240～260 ℃ annealing 4～6 minutes.

2. the preparation method with dilute magnetic semiconductor material of high-curie temperature according to claim 1 is characterized in that, the concentration of described Fe ion is 5.0～5.2%.

3. the preparation method with dilute magnetic semiconductor material of high-curie temperature according to claim 2 is characterized in that, the concentration of described Fe ion is 5.1%.

4. according to claim 1,2 or 3 described preparation methods, it is characterized in that the concentration of described 4H-SiC backing material is 10 with dilute magnetic semiconductor material of high-curie temperature ¹⁶Cm ^-3

5. the preparation method with dilute magnetic semiconductor material of high-curie temperature according to claim 1 is characterized in that, described pre-clean processes comprises step:

At first adopt the RCA of standard to clean, in concentration is 4～6% hydrofluoric acid, soak 18～22 seconds then after, dry.

6. the preparation method with dilute magnetic semiconductor material of high-curie temperature according to claim 1 is characterized in that, the process conditions of described injection Fe ion are:

The injection energy is 240～260keV; Injecting quantity is 3 * 10 ¹⁶Cm ^-2～5 * 10 ¹⁶Cm ^-2Temperature during injection is more than or equal to 300 ℃.

7. according to claim 5 or 6 described preparation methods, it is characterized in that with dilute magnetic semiconductor material of high-curie temperature, the process of described injection Fe ion, described backing material tilts 6～8 °.

8. the preparation method with dilute magnetic semiconductor material of high-curie temperature according to claim 1 is characterized in that, described HNH annealing process comprises:

At first under hydrogen atmosphere 300 ℃ annealing 5 minutes, then under nitrogen atmosphere 700 ℃ annealing 5 minutes, thereupon again under hydrogen atmosphere 250 ℃ annealing 5 minutes.

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