CN112599603A - Quasi-vertical field effect transistor based on longitudinal Schottky source tunneling junction and method - Google Patents

Quasi-vertical field effect transistor based on longitudinal Schottky source tunneling junction and method Download PDF

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CN112599603A
CN112599603A CN202011486346.9A CN202011486346A CN112599603A CN 112599603 A CN112599603 A CN 112599603A CN 202011486346 A CN202011486346 A CN 202011486346A CN 112599603 A CN112599603 A CN 112599603A
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layer
gate dielectric
quasi
field effect
effect transistor
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赵胜雷
宋秀峰
张进成
刘爽
吴银河
陈大正
王中旭
郝跃
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Xidian University
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Xidian University
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    • H01L29/0615Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE]
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Abstract

The invention discloses a quasi-vertical field effect transistor based on a longitudinal Schottky source tunneling junction and a method thereof, wherein the quasi-vertical field effect transistor comprises: the transistor comprises a substrate layer (1), an n + buffer layer (2), an n-drift layer (3), a gate dielectric layer (4), two drain electrodes (5), a grid electrode (6), two source electrodes (7) and four metal thickening layers (8). The device is enhanced, so that the noise suppression of the device and the safety of a circuit are improved, and the enhanced device has good compatibility with the conventional gate drive circuit. The invention can successfully avoid the problems of low activation rate of the P-type dopant, difficulty in realizing ohmic contact of the P-type material layer and the like in the wide bandgap semiconductor material. The invention controls the tunneling current of the Schottky source electrode by using the gate voltage, and can realize high current density.

Description

Quasi-vertical field effect transistor based on longitudinal Schottky source tunneling junction and method
Technical Field
The invention belongs to the technical field of semiconductor devices, and particularly relates to a quasi-vertical field effect transistor based on a longitudinal Schottky source tunneling junction and a method.
Background
With the decreasing of the available environmental resources, the performance requirements of high power semiconductor devices applied to power electronic equipment for power conversion and under high voltage and high current density are higher and higher, and the development of novel power devices with excellent performance and high conversion efficiency is one of the effective solutions for solving the conflict between energy and environment. For a high-power semiconductor device, the power quality factor of the high-power semiconductor device mainly depends on the breakdown voltage and the specific on-resistance of the device, but both of the devices often need to be optimized and designed comprehensively to effectively improve the performance of the power device. With the continuous development of the field of semiconductor power devices, the performance of the power devices is fundamentally changed from the first generation of Si materials to the second generation of GaAs materials.
However, so far, the performance of semiconductor power devices made of traditional two-generation materials has approached the theoretical limit determined by the material properties. The third generation semiconductor broadband materials represented by GaN have the characteristics of high frequency, high power, radiation resistance, high saturated electron mobility and the like, and have excellent potential in the aspect of power electronics. At present, GaN devices are mainly divided into lateral devices and vertical devices, the lateral devices represented by high-electron mobility transistors (HEMTs) have great advantages in the radio frequency field, and the vertical devices are more suitable for the power electronic field. Compared with a transverse device, the vertical device can improve the breakdown characteristic of the device only by increasing the thickness of the drift region of the device without sacrificing the transverse size of a chip, so that the vertical device has higher power density. In addition, the conducting channel of the vertical device is wide, the current density is high, and the conducting channel of the vertical device is located inside the device, so that the device is not easily influenced by a surface state and has good dynamic characteristics. The advantages mentioned above make the vertical device have the advantage of being extremely thick in the power electronics field. At present, the GaN vertical device mainly comprises three structures, namely, a CAVET (current aperture vertical electronic transistor), a trench MOSFET (trench metal oxide semiconductor field effect transistor) and a Fin.
For the CAVET structure, the device is a depletion mode device, the manufacturing process of the device is complex, the leakage under high-voltage bias is large, and the reliability is poor; although the trench MOSFET can easily realize enhancement, the process of the device is complicated, especially the ohmic contact of P-type GaN is difficult to realize, and in addition, the material damage caused by the etching process can also cause the degradation of the electron mobility of the channel, which affects the on-resistance of the device; although the Fin structure can also realize enhancement, the Fin structure has narrow conductive channel and small current density, and cannot meet the application requirement of high power.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a quasi-vertical field effect transistor based on a longitudinal Schottky source tunneling junction and a method. The technical problem to be solved by the invention is realized by the following technical scheme:
a quasi-vertical field effect transistor based on a vertical schottky source tunneling junction, comprising:
a substrate layer;
an n + buffer layer disposed on the substrate layer;
the n-drift layer is arranged on the n + buffer layer, and a groove is arranged on the n-drift layer;
the two source electrodes are respectively arranged at two ends of the upper surface of the n-drift layer;
the two drain electrodes are respectively arranged on the n + buffer layers positioned on the two sides of the n-drift layer;
the gate dielectric layers are arranged on the n + buffer layer, the side wall and the groove of the n-drift layer, the two drain electrodes and the two source electrodes, and the gate dielectric layers on the two drain electrodes and the two source electrodes are provided with through holes;
the grid electrode is arranged on the grid dielectric layer positioned in the groove of the n-drift layer 3, the lower surface of the grid electrode 6 is lower than the lower surfaces of the source electrodes 7, and the grid electrode is positioned between the two source electrodes;
four metal thickening layers, one metal thickening layer is arranged on the drain electrode and the gate dielectric layer at one end, the other metal thickening layer is arranged on the drain electrode and the gate dielectric layer at the other end, the other metal thickening layer is arranged on the source electrode and the gate dielectric layer at one end, the other metal thickening layer is arranged on the source electrode and the gate dielectric layer at the other end, and a gap is formed between the gate electrode and the metal thickening layers;
the n + buffer layer 2 and the n-drift layer 3 are made of the same material.
In one embodiment of the invention, the substrate layer is made of Si, GaN, AlN, SiC, GaO, sapphire, diamond or BN material.
In one embodiment of the present invention, the n + buffer layer and the n-drift layer are made of GaN, AlN, SiC, GaO, diamond, or BN materials.
In one embodiment of the present invention, the n + buffer layer has a doping concentration of 1018cm-3~1020cm-3The doping concentration of the n-drift layer is 1015cm-3~1017cm-3
In one embodiment of the invention, the source electrode is made of Ti/Au, W/Au, Mo/Au, Ni/Au, Pt/Au or Pd/Au, and the drain electrode is made of Ti/Al/Ni/Au, Ti/Al/Ti/Au, Ti/Al/Mo/Au, Ta/Al/Ta, Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
In one embodiment of the invention, the gate and the metal thickening layer are of the same material.
In one embodiment of the invention, the upper surface and the lower surface of the source electrode have an overlapping region with the gate electrode in a horizontal extension.
The invention also provides a preparation method of the quasi-vertical field effect transistor based on the longitudinal Schottky source tunneling junction, which is used for preparing the quasi-vertical field effect transistor in any one of the embodiments, and the preparation method comprises the following steps:
selecting a substrate layer;
growing an n + buffer layer on the substrate layer;
growing an n-drift layer on the n + buffer layer;
etching two ends of the n-drift layer to the surface of the n + buffer layer to expose the n + buffer layer;
manufacturing two drain electrodes on the exposed n + buffer layer;
manufacturing two source electrodes at two ends of the upper surface of the n-drift layer;
etching the n-drift layer between the two source electrodes to form a groove;
growing gate dielectric layers on the n + buffer layer, the side wall and the groove of the n-drift layer, the two drain electrodes and the two source electrodes;
and manufacturing a grid electrode on the grid dielectric layer positioned in the n-drift layer groove, and simultaneously preparing metal thickening layers on the two drain electrodes, the two source electrodes and the grid dielectric layer respectively.
In an embodiment of the present invention, after fabricating two drains on the exposed n + buffer layer, the method further includes:
and annealing the drain electrode to form ohmic contact.
In an embodiment of the present invention, the manufacturing a gate on the groove of the gate dielectric layer in the n-drift layer groove, and simultaneously respectively manufacturing metal thickening layers on the two drains, the two sources, and the gate dielectric layer, includes:
manufacturing a mask on the gate dielectric layer, and etching a metal thickening area window on the gate dielectric layer above the two drain electrodes and the gate dielectric layer above the two source electrodes;
and depositing grid metal on the grid dielectric layer and the metal thickening region window in the n-drift layer groove to form a grid and four metal thickening layers.
The invention has the beneficial effects that:
1. the device is enhanced, so that the noise suppression of the device and the safety of a circuit are improved, and the enhanced device has good compatibility with the conventional gate drive circuit.
2. According to the invention, a P-type material layer is not required, the material layer can be AlN, SiC, GaO, diamond and BN, wherein the SiC material does not have P-type dopant and has low activation rate, so that the problems of low activation rate of P-type dopants existing in other P-type material layers except the SiC material, difficulty in realizing ohmic contact of the P-type material layer and the like can be successfully avoided.
3. The invention controls the tunneling current of the Schottky source electrode by using the gate voltage, and can realize high current density.
4. The device has simple structure, does not need complex process flow, saves cost and improves the yield.
5. The device in the invention does not need PN junction, has high response speed and can be used as a high-speed device.
6. Due to the unique topological structure of the device, the parasitic triode effect does not exist, and the latch-up effect is eliminated.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a schematic structural diagram of a quasi-vertical field effect transistor based on a vertical schottky source tunneling junction according to an embodiment of the present invention;
fig. 2 is a schematic view of a manufacturing process of a vertical schottky source tunneling junction-based quasi-vertical field effect transistor according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.
Example one
Referring to fig. 1, fig. 1 is a schematic structural diagram of a vertical schottky source tunneling junction based quasi-vertical field effect transistor according to an embodiment of the present invention. The embodiment provides a quasi-vertical field effect transistor based on a longitudinal Schottky source tunneling junction, which comprises a substrate layer 1, an n + buffer layer 2, an n-drift layer 3, a gate dielectric layer 4, two drain electrodes 5, a gate electrode 6, two source electrodes 7 and four metal thickening layers 8, wherein the n + buffer layer 2 is arranged on the substrate layer 1, the n-drift layer 3 is arranged on the n + buffer layer 2, a groove is arranged on the n-drift layer 3, the two source electrodes 7 are respectively arranged at two ends of the upper surface of the n-drift layer 3, the two drain electrodes 5 are respectively arranged on the n + buffer layer 2 positioned at two sides of the n-drift layer 3, the gate dielectric layer 4 is arranged on the n + buffer layer 2, the side wall and the groove of the n-drift layer 3, the two drain electrodes 5 and the two source electrodes 7, and the gate dielectric layers 4 on the two drain electrodes 5 and the two source electrodes 7 are both provided with, the drain electrode 5 and the source electrode 7 are exposed, the grid electrode 6 is arranged on the grid medium layer 4 in the groove of the n-drift layer 3, the lower surface of the grid electrode 6 is lower than the lower surface of the source electrode 7, the grid electrode 6 is arranged between the two source electrodes 7, one metal thickening layer 8 is arranged on the drain electrode 5 and the grid medium layer 4 at one end, the other metal thickening layer 8 is arranged on the drain electrode 5 and the grid medium layer 4 at the other end, the other metal thickening layer 8 is arranged on the source electrode 7 and the grid medium layer 4 at one end, the other metal thickening layer 8 is arranged on the source electrode 7 and the grid medium layer 4 at the other end, a gap exists between the grid electrode 6 and the metal thickening layer 8, and the n + buffer layer 2 and the n-drift layer 3 are made of the.
Further, the material of the substrate layer 1 is Si, GaN, AlN, SiC, GaO, sapphire, diamond or BN material.
Furthermore, the n + buffer layer 2 is made of GaN, AlN, SiC, GaO, diamond or BN material, and the doping concentration of the n + buffer layer 2 is 1018cm-3~1020cm-3
Further, GaN, AlN, and S are used as the material of the n-drift layer 3iC. GaO, diamond or BN material, the doping concentration of the n-drift layer 3 being 1015cm-3~1017cm-3
Furthermore, the gate dielectric layer 4 is made of SiN or SiO2Or Al2O3Or HfO2A medium.
Further, the drain electrode 5 is made of Ti/Al/Ni/Au, Ti/Al/Ti/Au, Ti/Al/Mo/Au, Ta/Al/Ta, Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
Further, the gate electrode 6 and the metal thickening layer 8 are made of the same material.
Furthermore, the extension parts of the upper surface and the lower surface of the source electrode 7 in the horizontal direction have an overlapping region with the grid electrode 6, the bottom of the grid electrode 6 is lower than the bottom of the source electrode 7, and the grid electrode 6 and the source electrode 7 are electrically isolated by the grid dielectric layer 4.
The gate 6 and the source 7 have a partial overlap region, the gate 6 and the source 7 in the overlap region are electrically isolated by the gate dielectric layer 4, the overlap region is where the gate 6 and the source 7 overlap, electrons can tunnel from the source 7 to the n-drift layer 3 to conduct electricity, and then an interface above a tunneling interface is an interface overlapping the gate, which is equivalent to that the gate can control electron tunneling, so as to turn on or off the device.
Further, the material of the gate electrode 6 is Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
Further, the source electrode 7 is made of Ti/Au, W/Au, Mo/Au, Ni/Au, Pt/Au or Pd/Au.
The source electrode of the invention adopts specific metal, the source electrode metal and the n-drift layer form a Schottky junction, a grid electrode is arranged above the overlapping region, and the width of a Schottky barrier can be modulated by grid electrode voltage, so that the tunneling probability of electrons is changed, and the size of tunneling current is further controlled. When the grid voltage is lower than the threshold voltage, the Schottky barrier width is larger, the tunneling current is very small, and the device is in a turn-off state; when the gate voltage is higher than the threshold voltage, the schottky barrier width is narrowed, the tunneling current is rapidly increased, and the device is turned on.
The quasi-vertical field effect transistor can be used for power conversion of power electronic equipment and circuit control under high voltage and high current density.
1. The device is enhanced, so that the noise suppression of the device and the safety of a circuit are improved, and the enhanced device has good compatibility with the conventional gate drive circuit.
2. According to the invention, a P-type material layer is not required, the material layer can be AlN, SiC, GaO, diamond and BN, wherein the SiC material does not have P-type dopant and has low activation rate, so that the problems of low activation rate of P-type dopants existing in other P-type material layers except the SiC material, difficulty in realizing ohmic contact of the P-type material layer and the like can be successfully avoided.
3. The invention controls the tunneling current of the Schottky source electrode by using the gate voltage, and can realize high current density.
4. The device has simple structure, does not need complex process flow, saves cost and improves the yield.
5. The device in the invention does not need PN junction, has high response speed and can be used as a high-speed device.
6. Due to the unique topological structure of the device, the parasitic triode effect does not exist, and the latch-up effect is eliminated.
It should be noted that, the form of the metal material provided by the present invention is a/B, which means that the first layer is a and the second layer is B from bottom to top, for example, Ni/Au, means that the first layer is Ni and the second layer is Au from bottom to top.
Example two
Referring to fig. 2, fig. 2 is a schematic diagram illustrating a manufacturing process of a vertical schottky source tunneling junction-based quasi-vertical field effect transistor according to an embodiment of the present invention. The invention further provides a preparation method of the quasi-vertical field effect transistor based on the longitudinal Schottky source tunneling junction on the basis of the embodiment, and the preparation method comprises the following steps:
step 1, selecting a substrate layer 1.
Specifically, the surface of the substrate layer 1 is subjected to pretreatment for removing dangling bonds.
Further, the surface of the substrate layer 1 is cleaned and pretreated to remove dangling bonds on the surface of the substrate layer 1, andat a temperature of 900 ℃ to 1200 ℃ in the presence of H2And (3) an atmosphere reaction chamber for removing pollutants on the surface of the substrate layer 1 through heat treatment.
Preferably, the material of the substrate layer 1 is Si, GaN, AlN, SiC, GaO, sapphire, diamond or BN material.
And 2, growing an n + buffer layer 2 on the substrate layer 1.
Specifically, the n + buffer layer 2 is grown on the substrate layer 1 using an MOCVD (Metal-organic Chemical Vapor Deposition) process.
Further, the n + buffer layer 2 is made of GaN, AlN, SiC, GaO, diamond or BN material, and the doping concentration of the n + buffer layer 2 is 1018cm-3~1020cm-3
And 3, growing an n-drift layer 3 on the n + buffer layer 2.
Specifically, the n-drift layer 3 is grown on the n + buffer layer 2 using the MOCVD process.
Further, the material of the n-drift layer 3 adopts GaN, AlN, SiC, GaO, diamond or BN material, and the doping concentration of the n-drift layer 3 is 1015cm-3~1017cm-3
And 4, etching two ends of the n-drift layer 3 to the surface of the n + buffer layer 2 to expose the n + buffer layer 2.
Specifically, a mask is made on the n-drift layer 3, an RIE or ICP process is used to etch the opening region of the n-drift layer 3, and the etching is stopped until the n + buffer layer 2 is reached, so as to expose the n + buffer layer 2.
And then, annealing the etched sample wafer to repair the etching damage.
And 5, manufacturing two drain electrodes 5 on the exposed n + buffer layer 2.
Specifically, a drain metal is deposited on the exposed n + buffer layer 2 using a metal evaporation or magnetron sputtering process to fabricate two drains 5 on the n + buffer layer 2 on both sides of the n-drift layer 3.
Further, the drain electrode 5 is made of Ti/Al/Ni/Au, Ti/Al/Ti/Au, Ti/Al/Mo/Au, Ta/Al/Ta, Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
And 6, manufacturing two source electrodes 7 at two ends of the upper surface of the n-drift layer 3.
Specifically, a metal evaporation or magnetron sputtering process is adopted to deposit source metal at two ends of the upper surface of the n-drift layer 3 to form a source electrode 7, and the source electrode 7 and the n-drift layer 3 form a Schottky tunneling junction controlled by a grid electrode.
Further, the source electrode 7 is made of Ti/Au, W/Au, Mo/Au, Ni/Au, Pt/Au or Pd/Au.
And 7, etching the n-drift layer 3 between the two source electrodes 7 to form a groove.
Specifically, an RIE (reactive ion etching) or ICP (inductively coupled plasma) etching process is selected to etch the region to be etched of the n-drift layer 3 and expose the groove with the etching depth of 20 nm-100 nm, and the etching process adopts slow etching to reduce etching damage.
And 8, growing a gate dielectric layer 4 on the n + buffer layer 2, the side wall and the groove of the n-drift layer 3, the two drain electrodes 5 and the two source electrodes 7.
Specifically, a PEALD (Plasma Enhanced Atomic Layer Deposition) process is adopted to deposit the gate dielectric Layer 4 with the thickness of 10-30 nm on the n + buffer Layer 2, the side wall and the groove of the n-drift Layer 3, the two drain electrodes 5 and the two source electrodes 7.
And 9, manufacturing a grid electrode 6 in the groove of the grid dielectric layer 4, and simultaneously preparing metal thickening layers 8 on the two drain electrodes 5, the two source electrodes 7 and the grid dielectric layer 4 respectively.
And 9.1, manufacturing a mask on the gate dielectric layer 4, and etching a metal thickening area window on the gate dielectric layer 4 above the two drain electrodes 5 and the two source electrodes 7.
Specifically, a mask is manufactured on the gate dielectric layer 4 above the drain 5 and the source 7, and the gate dielectric layer 4 above the drain 5 and the source 7 is etched by adopting a dry etching process or a wet etching process to form metal thickened region windows of the drain 5 and the source 7.
And 9.2, depositing grid metal on the grid dielectric layer 4 and the metal thickening region window in the groove of the n-drift layer 3 to form a grid 6 and four metal thickening layers 8.
Specifically, a metal evaporation or magnetron sputtering process is adopted to deposit grid metal in the groove of the grid dielectric layer 4 and on the window of the metal thickening region to form a grid 6 and a metal thickening layer 8, and the metal thickening layer 8 is used for thickening the drain electrode 5 and the source electrode 7.
Further, there is a partial overlap region of the gate electrode 6 and the source electrode 7.
Further, the material of the gate electrode 6 is Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
EXAMPLE III
In this embodiment, a method for manufacturing a vertical schottky source tunneling junction-based quasi-vertical field effect transistor according to the present invention is described in a specific embodiment based on the above embodiments, where a substrate layer 1 in this embodiment is Si, a material for manufacturing is GaN, and a doping concentration is 1017cm-3The n-drift layer 3 is made of Al2O3The gate dielectric layer 4, the source electrode 7 made of Ti/Au, the drain electrode 5 made of Ti/Al/Ni/Au, and the quasi-vertical field effect transistor of the longitudinal Schottky source tunneling junction with the groove depth of 20nm are prepared by the following steps:
step 1, preprocessing for eliminating dangling bonds is carried out on the surface of a substrate layer 1 made of Si materials.
1.1, soaking the substrate layer 1 of the Si material in HF acid solution for 1min, sequentially placing the substrate layer 1 of the Si material in acetone solution, absolute ethyl alcohol solution and deionized water for ultrasonic cleaning for 10min respectively, and using N to clean the substrate layer 1 of the cleaned Si material2And (5) drying.
Step 1.2, cleaning and drying the substrate layer 1 of the Si material in the air H2And (3) performing heat treatment at the temperature of 1000 ℃ in the atmosphere reaction chamber to remove surface pollutants.
And 2, manufacturing an n + buffer layer 2 made of the GaN material.
Putting the substrate layer 1 of the pretreated Si material into an MOCVD system, introducing a Ga source, hydrogen and ammonia gas into a reaction chamber at the same time, and growing the Si material on the substrate layer 1 with the doping concentration of 1018cm-3An n + buffer layer 2 of GaN material.
And 3, manufacturing the n-drift layer 3 of the GaN material.
Putting the sample after the above process into the MOCVD system again,ga source, hydrogen and ammonia gas are simultaneously introduced into the reaction chamber, and the doping concentration of 10 is grown on the n + buffer layer 2 of the GaN material17cm-3An n-drift layer 3 of GaN material.
And 4, etching the n-drift layer 3.
A mask was made on the n-drift layer 3 of GaN material, and the sample was placed in an RIE system using Cl2And BCl3The gas etches the open area in the mask until the n + buffer layer 2, so as to expose the n + buffer layer 2.
And 5, repairing etching damage.
And placing the etched sample wafer in an RTP cavity, annealing for 10min at the high temperature of 450 ℃, and repairing etching damage.
And 6, manufacturing the drain electrode 5.
The sample is placed in a magnetron sputtering reaction chamber, aluminum, titanium, nickel and gold targets with the purity of 99.999 percent are utilized to deposit metal Ti/Al/Ni/Au on the left side and the right side of the upper surface of the exposed n + buffer layer 2 to be used as a drain electrode 5, and annealing is carried out for 30s under the high-temperature condition of 850 ℃ to form ohmic contact.
And 7, manufacturing a source electrode 7.
And directly placing the etched sample wafer in a magnetron sputtering reaction chamber, and depositing metal Ti/Au at two ends of the upper surface of the n-drift layer 3 by using titanium and gold targets with the purity of 99.999 percent to serve as a source electrode 7.
And 8, manufacturing a grid groove.
The sample was placed in a RIE system using Cl2And BCl3And etching the opening region in the mask to form a groove with the depth of 20nm between the two source electrodes 7 on the n-drift layer 3.
And 9, depositing a gate dielectric layer 4.
Putting the sample subjected to the steps into a plasma enhanced atomic layer deposition reaction chamber, and depositing 10 nm-thick Al on the side walls and the grooves of the n + buffer layer 2 and the n-drift layer 3, the two drain electrodes 5 and the two source electrodes 7 at the high temperature of 300 DEG C2O3As the gate dielectric layer 4.
And 10, manufacturing a source contact hole and a drain contact hole.
And manufacturing a mask on the gate dielectric layer 4, placing the sample in an RIE system, and etching the gate dielectric layer 4 above the source electrode 7 and the drain electrode 5 to form a source electrode contact hole and a drain electrode contact hole.
And 11, manufacturing a grid electrode 6 and thickening source electrode and drain electrode metal.
And manufacturing a mask on the gate dielectric layer 4 again, then placing the sample wafer in a magnetron sputtering reaction chamber, depositing metal Ni/Au as a grid 6 in a groove of the gate dielectric layer 4 by using nickel and gold targets with the purity of 99.999%, and thickening the source electrode 7 and the drain electrode 5 to form a metal thickening layer 8 so as to finish the manufacture of the whole device.
In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic data point described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims (10)

1. A quasi-vertical field effect transistor based on a longitudinal Schottky source tunneling junction, comprising:
a substrate layer (1);
an n + buffer layer (2), the n + buffer layer (2) being disposed on the substrate layer (1);
the n-drift layer (3), the n-drift layer (3) is arranged on the n + buffer layer (2), and a groove is arranged on the n-drift layer (3);
the two source electrodes (7) are respectively arranged at two ends of the upper surface of the n-drift layer (3);
the two drain electrodes (5) are respectively arranged on the n + buffer layer (2) positioned on two sides of the n-drift layer (3);
the gate dielectric layer (4), the gate dielectric layer (4) is arranged on the n + buffer layer (2), the side wall and the groove of the n-drift layer (3), the two drain electrodes (5) and the two source electrodes (7), and the gate dielectric layer (4) on the two drain electrodes (5) and the two source electrodes (7) is provided with a through hole;
the grid electrode (6) is arranged on the grid dielectric layer (4) in the groove of the n-drift layer (3), the lower surface of the grid electrode (6) is lower than the lower surfaces of the source electrodes (7), and the grid electrode (6) is positioned between the two source electrodes (7);
four metal thickening layers (8), one metal thickening layer (8) is arranged on the drain electrode (5) and the gate dielectric layer (4) at one end, the other metal thickening layer (8) is arranged on the drain electrode (5) and the gate dielectric layer (4) at the other end, the other metal thickening layer (8) is arranged on the source electrode (7) and the gate dielectric layer (4) at one end, the other metal thickening layer (8) is arranged on the source electrode (7) and the gate dielectric layer (4) at the other end, and a gap is formed between the gate electrode (6) and the metal thickening layers (8);
wherein the n + buffer layer (2) and the n-drift layer (3) are made of the same material.
2. Quasi-vertical field effect transistor according to claim 1, characterized in that the substrate layer (1) is of Si, GaN, AlN, SiC, GaO, sapphire, diamond or BN material.
3. Quasi-vertical field effect transistor according to claim 1, characterized in that the n + buffer layer (2) and the n-drift layer (3) both use GaN, AlN, SiC, GaO, diamond or BN materials.
4. Quasi-vertical field effect transistor according to claim 3, characterised in that the n + buffer layer (2) has a doping concentration of 1018cm-3~1020cm-3The doping concentration of the n-drift layer (3) is 1015cm-3~1017cm-3
5. Quasi-vertical field effect transistor according to claim 1, characterized in that the source (7) is made of Ti/Au, W/Au, Mo/Au, Ni/Au, Pt/Au or Pd/Au and the drain (5) is made of Ti/Al/Ni/Au, Ti/Al/Ti/Au, Ti/Al/Mo/Au, Ta/Al/Ta, Ni/Au, Pt/Au, Pd/Au, W/Au or Ni/Au/Ni.
6. Quasi-vertical field effect transistor according to claim 1, characterized in that the gate (6) and the metal thickening layer (7) are of the same material.
7. Quasi-vertical field effect transistor according to claim 1, characterized in that the upper and lower surfaces of the source (7) have an overlap region in the extension of the horizontal direction with the gate (6).
8. A method for preparing a quasi-vertical field effect transistor based on a longitudinal schottky source tunneling junction, which is used for preparing the quasi-vertical field effect transistor of any one of claims 1 to 7, and the preparation method comprises the following steps:
selecting a substrate layer (1);
growing an n + buffer layer (2) on the substrate layer (1);
growing an n-drift layer (3) on the n + buffer layer (2);
etching two ends of the n-drift layer (3) to the surface of the n + buffer layer (2) to expose the n + buffer layer (2);
-making two drains (5) on the exposed n + buffer layer (2);
two source electrodes (7) are manufactured at two ends of the upper surface of the n-drift layer (3);
etching the n-drift layer (3) between the two source electrodes (7) to form a groove;
growing gate dielectric layers (4) on the n + buffer layer (2), the side wall and the groove of the n-drift layer (3), the two drain electrodes (5) and the two source electrodes (7);
and manufacturing a grid electrode (6) on the gate dielectric layer (4) positioned in the groove of the n-drift layer (3), and simultaneously preparing metal thickening layers (8) on the two drain electrodes (5), the two source electrodes (7) and the gate dielectric layer (4) respectively.
9. Method for manufacturing a quasi-vertical field effect transistor according to claim 8, characterized in that after the two drains (5) are fabricated on the exposed n + buffer layer (2), it further comprises:
and annealing the drain electrode (5) to form ohmic contact.
10. Method for manufacturing a quasi-vertical field effect transistor according to claim 8, wherein a gate (6) is formed on the gate dielectric layer (4) in the recess of the n-drift layer (3), and metal thickening layers (8) are simultaneously formed on the two drains (5), the two sources (7) and the gate dielectric layer (4), respectively, comprising:
manufacturing a mask on the gate dielectric layer (4), and etching a metal thickening area window on the gate dielectric layer (4) above the two drain electrodes (5) and the gate dielectric layer (4) above the two source electrodes (7);
and depositing grid metal on the grid dielectric layer (4) in the groove of the n-drift layer (3) and the metal thickening region window to form a grid (6) and four metal thickening layers (8).
CN202011486346.9A 2020-12-16 2020-12-16 Quasi-vertical field effect transistor based on longitudinal Schottky source tunneling junction and method Pending CN112599603A (en)

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