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CN-121985545-A - Ga adopting inclined field plate and NiO heterojunction2O3Diode and preparation method thereof

CN121985545ACN 121985545 ACN121985545 ACN 121985545ACN-121985545-A

Abstract

The invention discloses a Ga 2 O 3 diode adopting an inclined field plate and a NiO heterojunction and a preparation method thereof, wherein the diode sequentially comprises a cathode ohmic contact electrode, an n-type Ga 2 O 3 substrate, an n-type Ga 2 O 3 epitaxial layer, a composite dielectric layer and an anode ohmic contact electrode positioned on the surface of a p-type oxide layer and part of the inclined field plate from bottom to top, wherein the composite dielectric layer comprises the p-type oxide layer and the inclined field plate, the orthographic projection of the inclined field plate surrounds the orthographic projection of the p-type oxide layer in the direction perpendicular to the plane where the n-type Ga 2 O 3 substrate is positioned, the section of the p-type oxide layer is in an inverted trapezoid shape, and the side wall at the juncture of the inclined field plate and the p-type oxide layer is provided with an inclination angle. The invention not only utilizes the depletion region of the pn junction formed by the P-type oxide layer and the n-type Ga 2 O 3 epitaxial layer to inhibit surface leakage current, but also utilizes the inclined field plate to disperse the edge electric field of the anode ohmic contact electrode, thereby realizing double homogenization of the bulk electric field and the surface electric field.

Inventors

  • ZHOU HONG
  • YANG YUWEI
  • WANG CHENLU
  • SUN SIHAN
  • ZHANG JINCHENG
  • HAO YUE

Assignees

  • 西安电子科技大学

Dates

Publication Date
20260505
Application Date
20260129

Claims (9)

  1. 1. A Ga 2 O 3 diode employing a slant field plate and NiO heterojunction, comprising: an n-type Ga 2 O 3 substrate; An n-type Ga 2 O 3 epitaxial layer located on the surface of the n-type Ga 2 O 3 substrate; the composite dielectric layer is positioned on one side surface of the n-type Ga 2 O 3 epitaxial layer far away from the n-type Ga 2 O 3 substrate, and comprises a p-type oxide layer and an inclined field plate, the orthographic projection of the inclined field plate surrounds the orthographic projection of the p-type oxide layer in the direction perpendicular to the plane of the n-type Ga 2 O 3 substrate, the section of the p-type oxide layer is in an inverted trapezoid shape, and the side wall of the junction of the inclined field plate and the p-type oxide layer is provided with an inclined angle; A cathode ohmic contact electrode positioned on one side surface of the n-type Ga 2 O 3 substrate far from the n-type Ga 2 O 3 epitaxial layer; and the anode ohmic contact electrode is positioned on one side surface of the p-type oxide layer and part of the inclined field plate far away from the n-type Ga 2 O 3 epitaxial layer.
  2. 2. The Ga 2 O 3 diode using a hetero-junction of a inclined field plate and NiO according to claim 1, wherein the inclined angle is an angle between a side wall of an intersection of the inclined field plate and the p-type oxide layer and a horizontal direction, and the inclined angle is in a range of 。
  3. 3. The Ga 2 O 3 diode employing a slant field plate and NiO heterojunction as defined in claim 1, wherein the material of the slant field plate is a high K dielectric comprising SiO 2 、HfO 2 、Al 2 O 3 or ZrO 2 .
  4. 4. The Ga 2 O 3 diode employing a slant field plate and NiO heterojunction as defined in claim 1, wherein the p-type oxide layer material comprises p-type NiO, p-type Cu 2 O, or p-type Co 3 O 4 .
  5. 5. The Ga 2 O 3 diode employing a slant field plate and NiO heterojunction as claimed in claim 1, wherein the n-type Ga 2 O 3 substrate has a crystal orientation of (001) and a Sn doping concentration of 。
  6. 6. A method for preparing a Ga 2 O 3 diode using a slant field plate and a NiO heterojunction, wherein the method is used for preparing a Ga 2 O 3 diode according to any one of claims 1 to 5; The method comprises the following steps: Providing an n-type Ga 2 O 3 substrate; Growing an n-type Ga 2 O 3 epitaxial layer on the surface of the n-type Ga 2 O 3 substrate; Manufacturing a cathode ohmic contact electrode on the surface of the n-type Ga 2 O 3 substrate, which is far away from one side of the n-type Ga 2 O 3 epitaxial layer; depositing a high-K dielectric on the surface of one side of the n-type Ga 2 O 3 epitaxial layer far away from the n-type Ga 2 O 3 substrate, removing part of the high-K dielectric by selective etching to form a groove, and forming a sloping field plate with sloping side walls by the residual high-K dielectric; depositing p-type oxide in the groove to form a p-type oxide layer with an inverted trapezoid cross section; And in the direction perpendicular to the plane of the n-type Ga 2 O 3 substrate, the orthographic projection of the anode ohmic contact electrode covers the orthographic projection of the p-type oxide layer and the orthographic projection of part of the oblique field plate.
  7. 7. The method of fabricating a Ga 2 O 3 diode using a slant field plate and NiO heterojunction as defined in claim 6, wherein a high-K dielectric is deposited on the surface of the n-type Ga 2 O 3 epitaxial layer on the side away from the n-type Ga 2 O 3 substrate, a portion of the high-K dielectric is removed by selective etching to form a trench, and the remaining high-K dielectric forms a slant field plate having sloped sidewalls, comprising: Depositing a high-K medium with the thickness of 150nm on the surface of one side of the n-type Ga 2 O 3 epitaxial layer far away from the n-type Ga 2 O 3 substrate by utilizing a plasma enhanced chemical vapor deposition PECVD technology; Defining an etching window on the high-K dielectric by adopting a photoetching process based on a preset inclined field plate inclination angle, exposing and developing to form a pattern; And taking the mixed gas of CF 4 /O 2 as etching gas, removing part of the high-K dielectric by dry etching to form a groove exposing part of the surface of the n-type Ga 2 O 3 epitaxial layer, and forming the inclined field plate by the residual high-K dielectric after etching, wherein the groove is provided with inclined side walls, and the high-K dielectric comprises SiO 2 、HfO 2 、Al 2 O 3 or ZrO 2 .
  8. 8. The method for manufacturing a Ga 2 O 3 diode using a slant field plate and NiO heterojunction as claimed in claim 7, wherein the step of depositing a p-type oxide layer with an inverted trapezoid cross section in the trench comprises: And depositing a p-type oxide layer in the groove by using a radio frequency magnetron sputtering technology, wherein the radio frequency power is 150W, and the target material is NiO ceramic with the purity of 99.99%.
  9. 9. The method for manufacturing a Ga 2 O 3 diode using a slant field plate and a NiO heterojunction according to claim 1, wherein the step of manufacturing a cathode ohmic contact electrode on the surface of the n-type Ga 2 O 3 substrate on the side far from the n-type Ga 2 O 3 epitaxial layer comprises: Ti/Au is deposited on the surface of the N-type Ga 2 O 3 substrate far away from the N-type Ga 2 O 3 epitaxial layer through an electron beam evaporation process, and rapid thermal annealing is carried out at 500 ℃ for 1 min in an N 2 environment, so that a cathode ohmic contact electrode is formed.

Description

Ga 2O3 diode adopting inclined field plate and NiO heterojunction and preparation method thereof Technical Field The invention belongs to the technical field of semiconductors, and particularly relates to a Ga 2O3 diode adopting an inclined field plate and a NiO heterojunction and a preparation method thereof. Background Gallium oxide (Ga 2O3) is used as an ultra-wide band gap semiconductor material, and has higher band gap width, critical breakdown field strength and Barbagn quality factor compared with wide band gap materials (such as silicon carbide and gallium nitride), so that the ultra-wide band gap semiconductor material has high power conversion efficiency and current processing capability. However, the gallium oxide material itself has a key limitation that a stable and reliable p-type doping process is lacking, which not only leads to that Ga 2O3 cannot form a high-quality PN junction structure, but also leads to that some mature edge termination technologies cannot be directly applied to a gallium oxide device, and the problem of electric field peak values at the edge of an anode ohmic contact electrode is particularly remarkable. In order to solve the problem of p-type gallium oxide deficiency, other p-type semiconductor materials are selected to replace p-type Ga 2O3 to form Heterojunction (HJ) in the prior art, or a dielectric layer (such as Al 2O3) is introduced at the edge of an anode ohmic contact electrode to serve as a field plate to disperse fringe electric fields. However, the existing design only adopts a single p-type heterojunction or a single dielectric field plate, and has certain optimization limitation that the 'pull-down' effect of the electric field on the lower surface of the single heterojunction is concentrated in the heterojunction region, the electric field peak value at the edge of the electrode is still higher, local breakdown is easy to occur, and the interface leakage current on the surface of Ga 2O3 cannot be restrained although the edge electric field can be relieved by the single dielectric field plate. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a Ga 2O3 diode adopting a slant field plate and a NiO heterojunction and a preparation method thereof. The technical problems to be solved by the invention are realized by the following technical scheme: In a first aspect, the present invention provides a Ga 2O3 diode employing a sloping field plate and a NiO heterojunction, comprising: an n-type Ga 2O3 substrate; An n-type Ga 2O3 epitaxial layer located on the surface of the n-type Ga 2O3 substrate; the composite dielectric layer is positioned on one side surface of the n-type Ga 2O3 epitaxial layer far away from the n-type Ga 2O3 substrate, and comprises a p-type oxide layer and an inclined field plate, the orthographic projection of the inclined field plate surrounds the orthographic projection of the p-type oxide layer in the direction perpendicular to the plane of the n-type Ga 2O3 substrate, the section of the p-type oxide layer is in an inverted trapezoid shape, and the side wall of the junction of the inclined field plate and the p-type oxide layer is provided with an inclined angle; A cathode ohmic contact electrode positioned on one side surface of the n-type Ga 2O3 substrate far from the n-type Ga 2O3 epitaxial layer; and the anode ohmic contact electrode is positioned on one side surface of the p-type oxide layer and part of the inclined field plate far away from the n-type Ga 2O3 epitaxial layer. In one embodiment of the invention, the inclination angle is the included angle between the side wall at the junction of the inclined field plate and the p-type oxide layer and the horizontal direction, and the range of the inclination angle is。 In one embodiment of the invention, the material of the oblique field plate is a high-K dielectric, and the high-K dielectric comprises SiO 2、HfO2、Al2O3 or ZrO 2. In one embodiment of the invention, the material of the p-type oxide layer comprises p-type NiO, p-type Cu 2 O or p-type Co 3O4. In one embodiment of the invention, the n-type Ga 2O3 substrate has a crystal orientation of (001) and a Sn doping concentration of。 In a second aspect, the invention also provides a preparation method of the Ga 2O3 diode adopting the oblique field plate and the NiO heterojunction, which is used for preparing the Ga 2O3 diode in the first aspect; The method comprises the following steps: Providing an n-type Ga 2O3 substrate; Growing an n-type Ga 2O3 epitaxial layer on the surface of the n-type Ga 2O3 substrate; Manufacturing a cathode ohmic contact electrode on the surface of the n-type Ga 2O3 substrate, which is far away from one side of the n-type Ga 2O3 epitaxial layer; depositing a high-K dielectric on the surface of one side of the n-type Ga 2O3 epitaxial layer far away from the n-type Ga 2O3 substrate, removing part of the high-K dielectric by selective etching to form a groove, and f