CN1388537A - Ion implantation process of preparing GaN-based diluted magnetic semiconductor material - Google Patents

Abstract

The method of preparing GaN-based dilute magnetic semiconductor film by ion implantation method, injecting magnetic ions such as Mn and Fe, Co or Ni into the GaN semiconductor film, that is, implanting magnetic ions with an energy of 150-250 keV by ion implantation, and then injecting magnetic ions at 850 Annealing treatment under -900℃, NH ₃ atmosphere. The DMS ion implantation method is a method of preparing magnetic semiconductors by implanting magnetic ions such as Fe, Mn, Co or Ni into GaN-based semiconductor materials by ion implantation. Compared with other direct growth methods, it can achieve higher ion doping concentration, so it is possible to prepare magnetic semiconductor materials with high Curie temperature.

Description

Method for preparing GaN-based diluted magnetic semiconductor material by ion implantation

1. Technical field

The invention relates to a method for preparing GaN-based dilute magnetic semiconductor film materials such as GaN:Mn by ion implantation

Law.

2. Technical background

Since the invention of the transistor, all applications of semiconductor electronics have been based on the exploration of electron charge. In the late twenties, a great deal of research effort began to focus on the application of electron spin. Devices exploiting the quantum nature of electron spin wave functions (spintronics) have made great strides in research into photoelectric conversion, ultrasensitive magnetic field sensors, and especially quantum-effect-based logic and memory devices for high-speed computing . However, the direct fusion of electronic materials (semiconductors) and spin materials (ferromagnetic metals) creates many problems due to the different nature of the materials (such as crystal structures, bonds, physical and chemical properties). Another solution is to use dilute magnetic semiconductors (semiconductors heavily doped with magnetic ions), which can be directly integrated with existing semiconductor devices.

Diluted Magnetic Semiconductor (DMS) is a new type of functional material that is doped with magnetic ions in non-magnetic semiconductors (such as IV-VI, II-VI or III-V) and uses carrier control technology to generate magnetism. . The magnitude of the magnetism can be altered by changing the carrier density in the dilute semiconductor material. Due to the exchange interaction between the local magnetic moments of magnetic ions and the energy-band electron spins, their photoelectric, magneto-optical, light absorption and transport properties can be effectively controlled by changing the concentration of magnetic impurities and the strength of the external magnetic field. It applies both electron charge and electron spin properties, so DMS devices can be directly integrated with existing semiconductor devices, and have important applications in new devices such as optical, electrical, and magnetic functional integration.

II-VI dilute magnetic semiconductor materials have been extensively studied. However, dilute semiconductors based on III-V groups have not been studied exhaustively. The Curie temperature (Tc) of (In, Mn) As and (Ga, Mn) As commonly studied at present is very low (35 and 110K). From the point of view of practical application, it is urgent to find materials with higher Curie temperature. Theoretical work suggests that wide bandgap semiconductors such as GaN and ZnO may be suitable representative materials capable of carrier-induced ferromagnetism at room temperature or higher. Gallium nitride and its related materials are the most promising materials in short-wavelength blue optoelectronics; and Mn _x Ga _1-x N belongs to the III-V diluted magnetic semiconductor materials with unique magnetic properties. Studies have shown that a relatively low Mn concentration is sufficient to make the corresponding Mn _x Ga _1-N ferromagnetic. Therefore, research on GaN-based DMS semiconductor materials has received sufficient attention in recent years.

The main difficulty faced by GaN-based DMS semiconductor materials is that there is no suitable growth method for direct epitaxial growth. Due to the low solubility of magnetic ions in GaN-based DMS materials, it is difficult to obtain epitaxial materials that do not form a second phase. The ion implantation process is a very convenient method to introduce different magnetic ions into different host materials. Compared with other direct growth methods, it can achieve higher ion doping concentrations and is easily used to prepare spin-polarized currents. Inject the device structure as a selective contact area. Therefore, ion implantation is a satisfactory alternative until a better direct epitaxial growth of GaN-based DMS semiconductor materials has not been found. Through ion implantation, magnetic ions such as Fe, Mn, Co or Ni are implanted into GaN-based semiconductor materials, which can be used to study the origin and nature of the ferromagnetism of DMS materials and prepare high-quality magnetic semiconductor materials.

In the present invention, we use the ion implantation method to inject magnetic ions such as Mn, Fe, Co or Ni into the GaN semiconductor thin film to prepare GaN-based room temperature ferromagnetic semiconductor thin film materials such as GaN:Mn and the like.

3. Technical content

The DMS ion implantation method is to inject magnetic ions such as Fe, Mn, Co or Ni into GaN-based semiconductor materials through ion implantation, which can be used to study the origin and nature of the ferromagnetism of DMS materials and prepare high-quality magnetic semiconductor materials. In the present invention, we use the ion implantation method to implant magnetic ions Mn, Fe, Co and Ni into GaN-based semiconductor films to prepare ferromagnetic semiconductor film materials with higher Curie temperature such as GaN:Mn.

The method for preparing a GaN-based diluted magnetic semiconductor thin film by ion implantation of the present invention is characterized in that magnetic ions such as Mn, Fe, Co or Ni are implanted into the GaN semiconductor thin film, that is, the ion implantation method is used to inject magnetic ions with an energy of 150 to 250 keV. ions, and then annealed at 850-900°C under NH ₃ atmosphere.

Using the method of ion implantation, we have successfully obtained GaN-based diluted magnetic semiconductor materials at room temperature. Such as GaN: Mn, its magnetic properties are shown in Figure 1. X-ray diffraction structure analysis shows that after Mn ions are implanted into GaN and annealed, Mn ions basically replace the Ga position in the GaN lattice, rather than the N-site or interstitial type. Because Ga and Mn both belong to the fourth period, their inner electron structure, electronegativity and atomic radius are similar, so that the lattice constant does not change much after Mn occupies the Ga site. In addition, the introduction of Mn leads to deep energy levels in GaN and makes the injection layer a semi-insulating material.

Mechanism and technical characteristics of the present invention are:

The DMS ion implantation method is a method for preparing magnetic semiconductors by implanting magnetic ions such as Fe, Mn, Co or Ni into GaN-based semiconductor materials through ion implantation. Compared with other direct growth methods, it can achieve higher ion doping concentration, so it is possible to prepare magnetic semiconductor materials with high Curie temperature. The implantation of high-energy ions before annealing disrupts the lattice of the GaN layer on the surface. After proper annealing, Mn has been activated and replaced the Ga position in the GaN lattice. GaN:Mn shows better quality.

4. Description of drawings

Figure 1 is the M-H curve of GaN:Mn film at room temperature

5. Specific implementation

1. First obtain high-quality GaN film samples, which can be obtained by metal-organic vapor phase epitaxy, molecular beam epitaxy or

GaN thin films grown by hydride vapor phase epitaxy and other methods. The GaN samples cited in the present invention are all made of gold

It is grown on a sapphire substrate by the method of organic vapor phase epitaxy (MOVPE), with a thickness of about 1 μm;

2. Using ion implantation equipment, implant magnetic ions Mn with an energy of 150-250 keV by means of ion implantation.

 Using the method of ion implantation to implant magnetic ions Mn with energy of 150-250keV, the concentration distribution of Mn

The peak is at 2000 Å, and the implantation concentration of Mn ions is 7×10 ²⁰ -2×10 ²² per cubic centimeter.

3. Annealing treatment at 900°C under NH ₃ atmosphere for 1 hour.

4. Similarly, according to the above steps, it is also possible to prepare magnetic semiconductors containing magnetic ions such as Fe, Co or Ni.

Material. The implantation concentration ranges of Fe, Co and Ni ions are the same as those of Mn ions, and the implantation conditions are similar.

Claims (2)

1, ion implantation prepares the method for GaN base dilution magnetic semiconductor film, it is characterized in that magnetic ion such as Mn and Fe, Co or Ni etc. are injected the GaN semiconductive thin film, promptly the method for injecting with ion is injected magnetic ion with the energy of 150～250keV, then at 850-900 ℃, NH ₃Annealing in process under the atmospheric condition.

2, the method that is prepared GaN dilution magnetic semiconductor film by the described ion implantation of claim 1, every cubic centimetre of the implantation concentration that it is characterized in that injecting magnetic ion is 7 * 10 ²⁰～2 * 10 ²²