阅读说明：本技术 太阳光盲区肖特基背栅金属氧化物半导体场效应光电晶体管 (Solar light blind area Schottky back grid metal oxide semiconductor field effect photoelectric transistor ) 是由 张春福 成亚楠 陈大正 冯倩 张进成 郝跃 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种基于转印氧化镓薄膜的肖特基背栅金属氧化物半导体场效应光电晶体管。其包括：包括：多晶硅栅(1)、SiO<Sub>2</Sub>介质层(2)、Ga<Sub>2</Sub>O<Sub>3</Sub>薄膜沟道层(3)、源极(4)和漏极(5)。所述Ga<Sub>2</Sub>O<Sub>3</Sub>薄膜沟道层(3)印制在SiO<Sub>2</Sub>介质层(2)上面的源极(4)与漏极(5)之间,所述源极(4)采用欧姆接触,所述漏极(5)采用肖特基接触,形成肖特基背栅复合结构。本发明结合肖特基二极管的单向导电特性和栅极可控这两个优点,提高了器件控制能力以及减小了反向漏电流,使得光暗电流比增加,增强了器件的可靠性,可用于火焰探测、保密空间通信、目标预警与跟踪和太阳盲成像。(The invention discloses a Schottky back gate metal oxide semiconductor field effect phototransistor based on a transfer printing gallium oxide film. It includes: the method comprises the following steps: polysilicon gate (1), SiO 2 Dielectric layer (2), Ga 2 O 3 A thin film channel layer (3), a source electrode (4), and a drain electrode (5). The Ga is 2 O 3 The thin film channel layer (3) is printed on SiO 2 Between a source electrode (4) and a drain electrode (5) on the dielectric layer (2), the source electrode (4) adopts ohmic contact, and the drain electrode (5) adopts Schottky contact to form a Schottky back gate composite structure. The invention combines the advantages of unidirectional conductivity and controllable grid of the Schottky diode, improves the control capability of the device, reduces reverse leakage current, increases the light-dark current ratio, enhances the reliability of the device, and can be used for flame detection,Secret space communication, target early warning and tracking and solar blind imaging.)

1. Solar light blind area Schottky back gate metal oxide semiconductorA field effect phototransistor, comprising: polysilicon gate (1), SiO₂Dielectric layer (2), Ga₂O₃A thin film channel layer (3), a source electrode (4) and a drain electrode (5), the Ga₂O₃The thin film channel layer (3) is printed on SiO₂Between source electrode (4) and drain electrode (5) on dielectric layer (2), source electrode (4) adopts ohmic contact, its characterized in that: the drain electrode (5) adopts Schottky contact to form a Schottky back gate composite structure.

2. The transistor of claim 1, wherein: the polysilicon gate (1) is used as the back gate of the transistor, and the thickness is 10-1000 nm; SiO 2₂The dielectric layer (2) is used as an oxide layer dielectric of the transistor, the thickness of the dielectric layer is 10-600nm, and the two parts form a back gate oxide layer from bottom to top.

3. The transistor of claim 1, wherein: the transfer Ga₂O₃The thickness of the thin film channel layer (3) is 100-400 nm.

4. The transistor of claim 1, wherein: the metal deposited on the source electrode and the drain electrode is an alloy formed by any one or more than two of Ti, Au, Cr, Pt and Ag, and the thickness of the metal is 10-1000 nm.

5. The transistor of claim 1, wherein: and the electrode distance between the source electrode and the drain electrode is 4-20 mu m.

6. A method for manufacturing a solar light blind area Schottky back gate metal oxide semiconductor field effect phototransistor is characterized by comprising the following steps:

(1) selected from the upper part and the lower part of SiO respectively₂Back gate oxide substrate of two parts of layer and polysilicon gate, wherein SiO₂The layer is used as an oxide layer medium of the transistor, namely a substrate, and the thickness of the layer is 10-600 nm; the polysilicon gate is used as a back gate, and the thickness is 10-1000 nm;

(2) ga is mixed with₂O₃The material is stripped along the 100 crystal direction toBlue gel and reduction of Ga by repeated tearing₂O₃Of a thickness of the Ga compound so that Ga remains on the blue gel₂O₃Printing the film on the selected substrate to form a channel layer;

(3) sequentially placing the transferred material in acetone, absolute ethyl alcohol and deionized water, respectively ultrasonically cleaning for 10min, and then blowing by using a nitrogen gun;

(4) adopting photoetching and electron beam evaporation processes to make a cross metal mark with numbers on the surface of the cleaned material, wherein the cross metal mark is used for marking the position of the transfer printing film;

(5) recording the position of the film by using a microscope, measuring the thickness of the film by using a step instrument, and selecting uniform Ga with the thickness of 100-400nm₂O₃A film;

(6) by photolithography on selected Ga₂O₃Forming a window with the thickness of 2 × 2 mu m on one side of the film, depositing metal with the thickness of 10-1000nm at the position of the opened window by adopting an electron beam evaporation process to form a source electrode, cleaning the metal and the photoresist at other parts by using acetone, cleaning by using absolute ethyl alcohol and deionized water, and drying by using a nitrogen gun;

(7) annealing at 500 deg.C in nitrogen atmosphere for 60s by rapid annealing technique to obtain source electrode and Ga₂O₃Forming an ohmic contact;

(8) by using the overlay technology, the source-drain distance is controlled to be 4-30 mu m through the layout, namely in Ga₂O₃And opening a window of 2 × 2 μm at the position 4-20 μm away from the source on the other side of the film, depositing metal with the thickness of 10-1000nm at the opened window by adopting an electron beam evaporation process to form a drain electrode, cleaning the metal and the photoresist at other parts by using acetone, cleaning by using absolute ethyl alcohol and deionized water, and blow-drying by using a nitrogen gun to finish the manufacture of the device.

7. The manufacturing method according to claim 6, wherein the step (4) of making the cross-shaped metal mark with numbers on the surface of the cleaned material is to transfer the number mark on the layout onto the surface of the material by using a photolithography technique, and then to deposit metal on the material by using an electron beam evaporation process to form the metal mark with numbers, wherein the deposited metal is an alloy formed by any one or more of Ti, Au, Cr, Pt and Ag, and the thickness is 20-500 nm.

Technical Field

The invention belongs to the technical field of semiconductor devices, and particularly relates to a Schottky contact back gate metal oxide semiconductor field effect photoelectric crystal MOSFEPT which can be used for flame detection, secret space communication, target early warning and tracking and sun blind imaging.

Technical Field

Gallium oxide Ga₂O₃Semiconductor materials have a long history, and as early as the 50 s of the 20 th century, the polycrystal of gallium oxide and the stable region thereof were first reported. However, gallium oxide was not appreciated at that time due to the limitations of the technology at that time. In recent years, with the development of science and technology, the potential advantages of gallium oxide in the fields of photoelectric detectors, electronic and power devices and the like are discovered, and related researches are more and more. According to statistics of related personnel, the number of applications related to gallium oxide is gradually increasing from the 50 s of the 20 th century.

Ga compared with other photodetectors₂O₃Photodetectors have a number of advantages: one is Ga₂O₃The semiconductor has good stability of strong radiation resistance, strong acid and strong alkali resistance and the like, and the other is Ga₂O₃The optical band gap of the transparent oxide semiconductor material is about 4.2eV to 5.1eV, and according to the relation between the absorption wavelength and the band gap, the absorption wavelength is mainly concentrated in a deep ultraviolet region, and the defect that the traditional transparent oxide semiconductor material is not transparent in the deep ultraviolet region is overcome. Due to the above advantages, Ga₂O₃Are often used for solar blind photodetectors. The solar blind photoelectric detector has great application potential for wide industries, civilian use, environments and organisms, and has attracted people's attention for potential application in the fields of flame detection, secret space communication, solar blind imaging and the like. How to explain the observed physical mechanism of the huge photoconductive gain is Ga₂O₃In the study of the following examples. From the rapid development of material epitaxy and device processes, Ga₂O₃The basic solar blind detector is the most likely solution to the deep ultraviolet UV detection technology for multifunctional applications to date.

The ultraviolet photoelectric detector is not easy to be interfered by long wave electromagnetic interference when working, can work in a strong electromagnetic radiation environment, has good concealment, does not transmit a detection signal to a target in a form of actively radiating electromagnetic waves outwards, but identifies the target by passively receiving ultraviolet radiation, and greatly avoids the exposure of the position of the ultraviolet photoelectric detector. The ultraviolet communication technology with great development potential utilizes ultraviolet rays as a medium, is hardly influenced by various electromagnetic interferences, has the characteristics of low eavesdropping rate and resolution, strong flexibility, all weather and the like, and belongs to a high-confidentiality communication technology.

At present, Ga based on transfer printing technology₂O₃The back gate mosfet is shown in fig. 1. The device 2 has a simple structure, and Ga is transferred on the back gate oxide layer substrate₂O₃And depositing a thin film, and depositing a source electrode and a drain electrode, wherein the two electrodes are in ohmic contact. Although Ga is used₂O₃The thin film has the advantages of small volume, less defects, cost saving and the like, but generally the structure has the defects of large dark current and long recovery process as a photoelectric detector, and Ga is used as the material₂O₃The material has low thermal conductivity, so that the temperature is too high in practical application, and the performance of the device is reduced.

Disclosure of Invention

The invention aims to optimize the performance of a device on the basis of the prior art, and provides a back gate metal oxide semiconductor field effect photoelectric transistor with a sunlight blind area Schottky contact and a manufacturing method thereof, so that the control capability and the light-dark current ratio of the device are enhanced, and the performance of the device is improved.

The key technology for realizing the purpose of the invention is to adopt a transfer printing technology to transfer β -Ga₂O₃The film is transferred on the back gate oxide layer substrate, and the Schottky-contacted Ga with the back gate structure is manufactured on the basis₂O₃The implementation scheme of the MOSFET of the material is as follows:

1. a solar dead zone Schottky contacted back gate metal oxide semiconductor field effect phototransistor comprises: back gate oxide layer, gallium oxide channel layer, drain and source, the source adoptsUsing ohmic contact with Ga transferred between drain and source₂O₃A thin film channel layer, characterized by: and the drain electrode adopts Schottky contact to form a Schottky back gate composite structure.

Further, the material of the back gate oxide layer comprises polysilicon gate and SiO₂Two parts of layer, polysilicon gate as back gate of transistor with thickness of 10-1000nm and SiO₂The layer is used as an oxide layer medium of the transistor and has the thickness of 10-600 nm.

Further, the transfer of Ga₂O₃The thickness of the thin film channel layer is 100-400 nm.

Furthermore, the source electrode and the drain electrode are made of any one or more than two of Ti, Au, Cr, Pt and Ag, the thickness of the alloy is 10-1000nm,

further, the electrode distance between the source electrode and the drain electrode is 4-20 μm.

2. A method for manufacturing a solar light blind area Schottky back gate metal oxide semiconductor field effect phototransistor is characterized by comprising the following steps:

(1) selected from the upper part and the lower part of SiO respectively₂Back gate oxide substrate of two parts of layer and polysilicon gate, wherein SiO₂The layer is used as an oxide layer medium of the transistor, namely a substrate, and the thickness of the layer is 10-600 nm; the polysilicon gate is used as a back gate, and the thickness is 10-1000 nm;

(2) ga is mixed with₂O₃The bulk material is peeled off in the 100 crystal direction onto the blue gel and Ga is reduced by repeated tearing₂O₃Thickness of (b), Ga after final tearing₂O₃Transferring the film to a selected substrate;

(3) sequentially placing the transferred material in acetone, absolute ethyl alcohol and deionized water, respectively ultrasonically cleaning for 10min, and then blowing by using a nitrogen gun;

(4) adopting photoetching and electron beam evaporation processes to make a cross metal mark with numbers on the surface of the cleaned material, wherein the cross metal mark is used for marking the position of the transfer printing film;

(5) recording the position of the film by using a microscope, measuring the thickness of the film by using a step instrument, and selecting the thicknessUniform Ga of 100-400nm₂O₃A film;

(6) by photolithography on selected Ga₂O₃Forming a window with the thickness of 2 × 2 mu m on one side of the film, depositing metal with the thickness of 10-1000nm at the position of the opened window by adopting an electron beam evaporation process to form a source electrode, cleaning the metal and the photoresist at other parts by using acetone, cleaning by using absolute ethyl alcohol and deionized water, and drying by using a nitrogen gun;

(7) annealing at 500 deg.C in nitrogen atmosphere for 60s by rapid annealing technique to obtain source electrode and Ga₂O₃Forming an ohmic contact;

(8) by using the overlay technology, the source-drain distance is controlled to be 4-30 mu m through the layout, namely in Ga₂O₃And opening a window of 2 × 2 μm at the position 4-20 μm away from the source on the other side of the film, depositing metal with the thickness of 10-1000nm at the opened window by adopting an electron beam evaporation process to form a drain electrode, cleaning the metal and the photoresist at other parts by using acetone, cleaning by using absolute ethyl alcohol and deionized water, and blow-drying by using a nitrogen gun to finish the manufacture of the device.

Compared with the prior art, the invention has the following advantages:

compared with the traditional back gate MOSFET device, the Schottky back gate composite structure is adopted, the output current of the transistor under the unopened state is smaller and the dark current is reduced due to the existence of Schottky contact, and the light-dark current ratio is increased under the condition that the photocurrent is not changed, so that the detection sensitivity and accuracy of the photoelectric detector are improved; compared with the prior transfer Ga₂O₃Due to the existence of the back gate, the thin film Schottky diode structure enhances the control capability of a conductive channel, improves the working frequency of a device and reduces power loss.

Drawings

FIG. 1 is a prior art transfer-based Ga₂O₃A schematic of a back gate mosfet ept device;

FIG. 2 is a schematic cross-sectional structure of the present invention;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a drawing of the present inventionGa for Schottky contact₂O₃A flow diagram of a back gate mosfet ept device;

FIG. 5 is a cross metal mark made in the method of the present invention.

Detailed Description

Embodiments of the invention are described in further detail below with reference to the accompanying drawings.

Referring to fig. 2 and 3, the present invention is a transfer printing technology-based solar blind area schottky contact Ga₂O₃The back gate MOSFET comprises polysilicon gate 1 and SiO₂Substrate 2, Ga₂O₃A thin film channel layer 3, a source electrode 4 and a drain electrode 5. Wherein SiO is₂The thickness of the substrate 2 is 10-600nm, and the substrate is used as an oxide layer medium of a transistor; the thickness of the polysilicon gate 1 is 10-1000nm, and the polysilicon gate is positioned on SiO₂The lower portion of the substrate 2 serves as the back gate of the transistor, and these two portions constitute a back gate oxide layer. Ga₂O₃The thin film channel layer 3 is printed on SiO₂On the substrate 2, between the source 4 and the drain 5 in the portion of thickness 100-400nm, the source 4 and the drain 5 are located in Ga₂O₃The electrode distance between the two sides of the thin film channel layer 3 is 4-20 μm.

The source electrode 4 adopts ohmic contact, the deposited metal is an alloy formed by any one or more than two of Ti, Au, Cr, Pt and Ag, and the thickness is 10-1000 nm; the drain electrode 5 adopts Schottky contact, the deposited metal is also an alloy formed by any one or more than two of Ti, Au, Cr, Pt and Ag, and the thickness is 10-1000 nm; the drain and source metal materials may be the same or different, and the metal thicknesses may be the same or slightly different.

Referring to fig. 4, the method of the present invention for making a schottky contact back gate mosfet of a transfer-printed gallium oxide thin film includes the following three embodiments.