CN-116525725-B - Method for improving hole concentration of p-type III-nitride material and application thereof

Abstract

The invention discloses a method for improving the hole concentration of a p-type III-nitride material and application thereof. The method includes contact reacting a p-type group III nitride material with halogen-based reactive atoms and/or halogen-based reactive groups during and/or after growth of the p-type group III nitride material to remove a portion of the group III atoms in the p-type group III nitride material, thereby creating cation vacancies in the p-type group III nitride material, and activating acceptor impurities in the p-type group III nitride material that include the cation vacancies. The method for improving the hole concentration of the AlGaN semiconductor material breaks through the limitations of low incorporation efficiency of acceptor type Mg atoms, serious self-compensation effect and the like faced by the traditional p-type AlGaN material, and can greatly improve the concentration of Mg acceptor type impurities at lattice sites of III-group atoms by utilizing III-group cation vacancies, thereby obviously improving the hole concentration in the p-type AlGaN material.

Inventors

• SUN QIAN
• LIU JIANXUN
• HUANG YINGNAN
• SUN XIUJIAN
• FENG MEIXIN
• YANG HUI

Assignees

• 中国科学院苏州纳米技术与纳米仿生研究所

Dates

Publication Date

20260505

Application Date

20220120

Claims (15)

1. 1. A method for increasing the hole concentration of a p-type group III nitride material, comprising: contacting and reacting the p-type group III nitride material with halogen-based reactive atoms and/or halogen-based reactive groups during and/or after growth of the p-type group III nitride material to remove a portion of the group III atoms in the p-type group III nitride material, thereby creating cation vacancies in the p-type group III nitride material, and Acceptor impurities in a p-type group III nitride material containing the cation vacancies are activated.
2. 2. The method according to claim 1, characterized in that it comprises: When growing p-type III-nitride material in a reaction chamber, inputting a halogen-based source into the reaction chamber, wherein the halogen-based source can form the halogen-based active atoms and/or halogen-based active groups at the growth temperature of the p-type III-nitride material, and enabling the p-type III-nitride material to contact and react with the halogen-based active atoms and/or halogen-based active groups so as to remove part of III-atoms in the p-type III-nitride material, thereby generating cation vacancies in the p-type III-nitride material.
3. 3. The method of claim 2, further comprising withdrawing p-type group III nitride material containing the cation vacancies from the reaction chamber and reactivating acceptor impurities therein.
4. 4. The method of claim 1, comprising inputting a halogen-based source into a reaction chamber containing a p-type group III nitride material and causing the halogen-based source to form the halogen-based reactive atoms and/or halogen-based reactive groups and causing a contact reaction of the surface of the p-type group III nitride material with the halogen-based reactive atoms and/or halogen-based reactive groups to remove a portion of the group III atoms near the surface of the p-type group III nitride material, thereby forming a thin layer of cation vacancies near the surface of the p-type group III nitride material, the thin layer of cation vacancies comprising a plurality of cation vacancies.
5. 5. The method according to claim 4, characterized in that it comprises in particular: S1, inputting a III-group metal source, an acceptor impurity source and a nitrogen source into the reaction chamber, so as to grow and form a p-type III-group nitride material; S2, stopping inputting a III-group metal source and an acceptor impurity source into the reaction chamber, inputting a halogen-based source into the reaction chamber, enabling the halogen-based source to form the halogen-based active atoms and/or halogen-based active groups, enabling the surface of the p-type III-group nitride material to contact and react with the halogen-based active atoms and/or halogen-based active groups, and removing part of III-group atoms near the surface of the p-type III-group nitride material, so that a thin-layer cation vacancy layer is formed near the surface of the p-type III-group nitride material; S3, circularly repeating the steps S1-S3 for more than one time until a p-type III nitride material layer with the required thickness is obtained; and S4, activating acceptor impurities in the p-type III-nitride material layer finally obtained in the step S3.
6. 6. The method as recited in claim 5, further comprising: And S2x, after the step S2 is completed, introducing an acceptor impurity source and maintaining for 0-60S to promote the acceptor impurity to fully occupy the III-group cation vacancies, and then performing the step S3.
7. 7. The method according to claim 6, wherein the method comprises, the method is characterized in that the method further comprises the following steps: and S3x, after the step S3 is completed, continuing to grow a semiconductor material layer or a non-semiconductor material layer on the p-type III-nitride material layer, and then performing step S4.
8. 8. The method according to claim 5, 6 or 7, comprising continuously completing the operations of steps S1-S4 in the same reaction chamber.
9. 9. The method of claim 1, wherein the p-type group III nitride material comprises a poly-group III nitride.
10. 10. The method of claim 9, wherein the group III nitride includes In x Al y Ga 1-x- y N、B x Al 1-x N or B x Al y Ga 1-x-y N, 0≤x≤1, 0≤y≤1.
11. 11. The method according to claim 2, wherein the halogen-based source comprises any one of an elemental halogen, an organic compound containing a halogen element, and an inorganic compound containing a halogen element.
12. 12. The method of claim 11, wherein the halogen-based source comprises any one or a combination of two or more of t-butyl chloride, hydrogen chloride, chlorine, and tetrachloromethane.
13. 13. The method of claim 1, wherein the acceptor impurity comprises any one or a combination of Mg, zn, be, C.
14. 14. A method of making an ohmic contact to a p-type group III nitride semiconductor material, comprising: Increasing the hole concentration of a p-type group III nitride material using the method of any of claims 1-13; an electrode is fabricated and ohmic contact is made to the p-type group III nitride material.
15. 15. A method of making an ultraviolet light electronic device comprising: a first step of fabricating a body structure of an ultraviolet light electronic device, and A second step of making an electrode mated with the body structure; Characterized in that the first step further comprises: the method of any one of claims 1-13 being used to increase the hole concentration of a p-type group III nitride material.

Description

Method for improving hole concentration of p-type III-nitride material and application thereof Technical Field The invention particularly relates to a method for improving the hole concentration of a p-type III-nitride material and application thereof, and belongs to the technical field of semiconductors. Background The AlGaN semiconductor material is a direct and wide-band gap semiconductor material, the forbidden band width is continuously adjustable between 3.4eV and 6.2eV, the wavelength range covers the near ultraviolet band to the deep ultraviolet band, the AlGaN semiconductor material is an ideal material for preparing ultraviolet electronic devices such as LEDs, lasers, detectors and the like, and the AlGaN semiconductor material has wide application prospects in the fields of general illumination, ultraviolet sterilization and disinfection, solar blind detection and the like. For PN junction devices such as AlGaN-based LEDs and laser PiN detectors, high-quality and low-resistivity ohmic contact is one of the necessary conditions for improving the performance and reliability of the devices. However, the ohmic contact preparation of the p-type AlGaN material is very difficult because the p-type AlGaN material has a large forbidden bandwidth and a high work function (more than 7.5 eV), and the Pt metal with the highest work function existing in nature is only 5.65eV, so that the metal with the high work function is matched with the p-type AlGaN, so that a high potential barrier is formed when the metal is contacted with the p-type AlGaN, and hole carriers can pass through the gap-type AlGaN material only by being excited by a high electric field. The width of a metal/p-type AlGaN contact potential barrier can be reduced by improving the hole concentration of the p-type AlGaN material, and the hole tunneling is enhanced, so that the ohmic contact resistance is reduced. However, the p-type AlGaN material has a large forbidden bandwidth, high ionization energy of an Mg acceptor and low ionization rate of the Mg acceptor (less than 10%), so that the concentration of holes in the material is usually low (basically on the order of 10 17cm-3 or lower), which directly leads to an increase in the width of a depletion region of the metal/p-type AlGaN and a decrease in the probability of hole tunneling, and thus has high ohmic contact resistance. The high ohmic contact resistance and series resistance of the P-type AlGaN material lead to high working voltage and high thermal power of the device, so that the working junction temperature of the device is high, and the performance and reliability of the device are seriously affected. Therefore, the development of ohmic contact technology for p-type AlGaN materials has become an urgent need for AlGaN-based deep ultraviolet materials and device development. In order to make ohmic contacts to p-type AlGaN materials, it is desirable to increase the concentration of holes near the surface as much as possible to reduce the gold/semiconductor contact depletion region and enhance hole tunneling. However, due to the large forbidden bandwidth, high ionization energy of the Mg acceptor (more than 150meV, and much higher than 26meV of thermal energy at room temperature), the hole concentration in p-type AlGaN semiconductor materials is often low (basically on the order of 10 17cm-3 or lower), 1-2 orders of magnitude lower than the electron concentration, and 1-2 orders of magnitude lower than the electron mobility, which directly results in 1) asymmetric transport of electrons and holes, and low quantum efficiency of the device. Due to the low mobility of holes and high mobility of electrons, the electron-hole recombination occurs basically in the quantum well near the p side, and thus the recombination efficiency is low. Meanwhile, the electron concentration is 1-2 orders of magnitude higher than the hole concentration, excessive hot electrons which do not generate recombination easily overflow the quantum well and overshoot to the p-type AlGaN, and a large amount of heat is generated due to the capture of material defects, so that the quantum efficiency of the device is rapidly reduced, the reliability is reduced, and 2) the bulk resistivity and the series resistance of the p-type AlGaN material are high. For the AlGaN material with high Al component, the problem is more serious because the forbidden bandwidth of the material is larger and the ionization energy of the Mg acceptor is further improved. The higher series resistance can lead to high working voltage and large heating value of the device, so that the working junction temperature of the device is high, and the performance and reliability of the device are seriously affected. The conventional method for increasing the hole concentration of p-type AlGaN by heavily doping Mg atoms has great limitation. On the one hand, as the Al component increases, the activation energy of the acceptor impurity of Mg is obviously imp