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CN-115863436-B - Diamond field effect transistor and preparation method thereof

CN115863436BCN 115863436 BCN115863436 BCN 115863436BCN-115863436-B

Abstract

The invention discloses a diamond field effect transistor and a preparation method thereof, wherein the diamond field effect transistor comprises a diamond substrate, a single crystal diamond epitaxial film, a source electrode, a drain electrode, a stress regulation film and a gate electrode; the diamond substrate is provided with a single crystal diamond epitaxial film, the single crystal diamond epitaxial film is provided with a hydrogen terminal area and an oxygen terminal area, the hydrogen terminal area is a channel area formed by a two-dimensional hole gas conducting layer, two ends of the channel area are respectively provided with a source electrode and a drain electrode, the channel area without the source electrode and the drain electrode is provided with a stress regulating film, and the gate electrode is arranged on the stress regulating film and the oxygen terminal area. The invention introduces the stress regulation film, can enhance the carrier mobility through stress regulation based on the stress regulation film, and does not damage the performance of the conducting channel.

Inventors

  • WANG WEI
  • ZHANG MINGHUI
  • WEN FENG
  • BU RENAN
  • WANG HONGXING
  • HOU XUAN
  • LIANG YUESONG
  • NIU TIANLIN
  • XIONG YICHENG
  • CHEN GENQIANG
  • FENG YONGCHANG
  • FANG PEIYANG
  • WANG YANFENG
  • LIN FANG

Assignees

  • 西安交通大学

Dates

Publication Date
20260508
Application Date
20221212

Claims (10)

  1. 1. The diamond field effect transistor is characterized by comprising a diamond substrate (1), a single crystal diamond epitaxial film (2), a source electrode (3), a drain electrode (4), a stress regulating film (6) and a gate electrode (7); The single crystal diamond epitaxial film (2) is arranged on the diamond substrate (1), a hydrogen terminal area and an oxygen terminal area (8) are arranged on the single crystal diamond epitaxial film (2), and the hydrogen terminal area is a channel area (5) formed by a two-dimensional hole gas conducting layer; the source electrode (3) and the drain electrode (4) are respectively arranged at two ends of the channel region (5); The stress regulation film (6) is arranged on the source electrode (3), the drain electrode (4) and a channel region (5) without the source electrode and the drain electrode, and the stress regulation film (6) is used for regulating and controlling the stress of the monocrystalline diamond epitaxial film (2) and the channel region (5) below the stress regulation film so as to improve the carrier mobility of the two-dimensional hole gas conducting layer; the gate electrode (7) is disposed on the stress control film (6) and the oxygen termination region (8).
  2. 2. A diamond field effect transistor according to claim 1, wherein the stress controlling film (6) is of SiN x 、SiO 2 、Al 2 O 3 、HfO 2 、ZrO 2 , diamond like carbon or other material with a work function of 5eV or more.
  3. 3. A diamond field effect transistor according to claim 1, wherein the stress controlling film (6) has a thickness of 1nm to 5000nm.
  4. 4. The diamond field effect transistor according to claim 1, wherein the stress regulating film (6) has an internal pressure stress of 1mpa to 10gpa.
  5. 5. The diamond field effect transistor according to claim 1, wherein the compressive stress in the single crystal diamond epitaxial film (2) below the stress control film (6) is 10mpa to 5gpa.
  6. 6. A diamond field effect transistor according to claim 1, wherein the channel region (5) has a width of 5nm to 100 μm, a carrier concentration in the channel of 1 x 10 12 cm -2 ～5×10 14 cm -2 , and a mobility of 20cm 2 /V·s～2500cm 2 /v.s.
  7. 7. The diamond field effect transistor according to claim 1, wherein the source electrode (3) and the drain electrode (4) are made of Au, pd, ir, pt or Ti, and the gate electrode (7) is made of Al, zr, hf or Mo.
  8. 8. A method of manufacturing a diamond field effect transistor according to claim 1, comprising the steps of: Homoepitaxial monocrystalline diamond film on the cleaned diamond substrate (1) to obtain monocrystalline diamond epitaxial film (2); carrying out hydrogenation treatment on the monocrystal diamond epitaxial film (2) to obtain a two-dimensional hole gas conducting layer; Forming source electrode and drain electrode patterns on the two-dimensional hole gas conducting layer, correspondingly depositing source electrode metal and drain electrode metal, and obtaining ohmic contact of the source electrode (3) and the drain electrode (4) by utilizing a stripping technology; Covering photoresist on a source electrode (3), a drain electrode (4) and a channel region (5) between the source electrode and the drain electrode, and performing oxygen termination treatment by using a photoetching technology to form an oxygen termination region (8) so as to realize electrical isolation of the device; depositing a stress regulating film (6) on the source electrode (3), the drain electrode (4) and a channel region (5) between the source electrode and the drain electrode, regulating the internal pressure stress of the stress regulating film (6) to meet preset requirements; And forming a gate electrode (7) pattern on the stress control film (6) and the oxygen terminal area (8), depositing gate electrode metal, and obtaining the gate electrode (7) by using a stripping technology.
  9. 9. The method of manufacturing a diamond field effect transistor according to claim 8, wherein in the step of depositing the stress controlling film (6) on the source electrode (3), the drain electrode (4) and the channel region (5) therebetween, The deposition mode adopts electron beam evaporation, sputtering, atomic layer deposition, plasma enhanced chemical vapor deposition or low-pressure gas phase chemical deposition.
  10. 10. The method of manufacturing a diamond field effect transistor according to claim 8, wherein in the step of controlling the magnitude of the internal pressure stress of the stress controlling film (6) to meet a predetermined requirement, The regulation mode adopts ion implantation, thermal annealing, multilayer deposition or ultraviolet ray auxiliary heat treatment technology.

Description

Diamond field effect transistor and preparation method thereof Technical Field The invention belongs to the technical field of semiconductor devices, and particularly relates to a diamond field effect transistor and a preparation method thereof. Background With the application of the first generation semiconductor materials silicon (Si) and germanium (Ge) in the field of electronic devices, the human science and technology life enters an express way, the second generation semiconductor materials gallium arsenide (GaAs), the third generation semiconductor materials silicon carbide (SiC) and gallium nitride (GaN) are developed and utilized successively under the promotion of technological progress and the development requirement of integrated circuits, the moore's law requires that more electronic devices are integrated in a unit area, the problems of heat dissipation, gate breakdown, tunneling leakage current and the like of the devices are increasingly prominent, and people gradually turn the eyes to the emerging semiconductor materials to solve the problems. The performances of diamond and other semiconductor materials are compared, the diamond has wide forbidden bandwidth, high mobility, large thermal conductivity and large Johnson, baliga and Keyes quality factors, as shown in table 1, the table 1 is the comparison data of the diamond material quality factors and Si, gaN, siC, and the electrical performance is obviously superior to that of other three-generation semiconductor materials, so that the performance of a diamond-based electronic device is superior to that of other semiconductor electronic devices, the application fields of output power and working frequency are covered maximally, and the diamond-based electronic device is very suitable for preparing ultrahigh-frequency, ultrahigh-power, high-temperature-resistant and radiation-resistant electronic devices. Therefore, the method has great application potential in the fields of aerospace, advanced equipment and the like with very high requirements on material volume, weight, heat dissipation, power density and reliability. TABLE 1 comparison of the quality factors of diamond materials with Si, gaN, siC data MaterialJohnson indexKeyes indexBaliga index [ Si=1 ]Diamond diamond253014543938SiC91035620GaN756104870Si111 Experiments prove that electrons in a diamond valence band on the surface of a hydrogen terminal are transferred to the lowest unoccupied molecular orbit (LOMO) in adsorption molecules, so that a layer of two-dimensional hole gas (2 DHG) is formed on the surface of the diamond, the carrier concentration of the surface about 10 13cm-2 and the carrier mobility in the range of 20-680cm 2·V-1·s-1 can be obtained, and the theoretical prediction shows that the mobility can be larger than 3000cm 2·V-1·s-1 after interface ionized impurity scattering and roughness scattering are solved. When the traditional element doping is not solved, the two-dimensional hole gas can be used as a conductive channel of a field effect transistor, so that the development of a diamond FET is greatly promoted, however, the hydrogen terminal diamond has smaller transfer doping dipole moment due to the limitation of the surface terminal bond length, and channel carrier transport scattering is increased, so that the mobility is generally lower. In recent years, the enhancement of the carrier mobility of a conducting channel on the surface of a hydrogen-terminated diamond is realized by methods such as epitaxial high-quality diamond layer, amorphous carbon adsorption, introduction of a high-dielectric constant material to enhance dielectric shielding and the like, but the actual enhancement effect is limited, the channel carrier mobility, such as h-BN, can be improved by passivating the surface of the hydrogen-terminated diamond based on a two-dimensional material, and mainly because the two-dimensional material can passivate the surface state of the hydrogen-terminated diamond, part of charges can be transferred on the outer surface of the two-dimensional material, the charge acting distance is increased, the surface scattering is reduced, and the carrier mobility is obviously improved. Disclosure of Invention The present invention is directed to a diamond field effect transistor and a method for manufacturing the same, which solve one or more of the above-mentioned problems. The diamond field effect transistor provided by the invention is introduced with the stress regulation film, and the carrier mobility can be enhanced through stress regulation based on the stress regulation film without damaging the performance of a conductive channel. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a diamond field effect transistor, which comprises a diamond substrate, a monocrystalline diamond epitaxial film, a source electrode, a drain electrode, a stress regulation film and a gate electrode; The single crysta