135 results about "Electric-field screening" patented technology

The invention provides a semiconductor device and a manufacturing method thereof, the semiconductor device comprises a semiconductor layer and a trench gate, the trench gate is located in a trench of a first surface of the semiconductor layer, and the semiconductor layer comprises a body region, a source region and a drift region; the first buried layer is located at the bottom of the trench gate and connected with the trench gate, the third buried layer is connected with a part of the first buried layer in the width direction of the trench gate, and the third buried layer is further connected with a part of the body region. The first buried layer is arranged at the bottom of the trench gate, the voltage endurance capability is improved, and the first buried layer is electrically connected with the source region through the third buried layer, the body region and the source region in sequence, so that the electric field shielding function of the first buried layer to the bottom of the trench gate is more stable.

The invention provides a semiconductor structure and a forming method thereof, and the semiconductor structure comprises a semiconductor substrate, an epitaxial layer is formed on the first surface of the semiconductor substrate, and a plurality of junction implants are formed in the epitaxial layer; the JFET region is positioned among the plurality of junction implants, and the distance between two adjacent junction implants in the plurality of junction implants is defined as a JFET gap; the plurality of buried injection regions are located in part of the JFET region, the top surface of each buried injection region is lower than the top surface of the JFET region, and the doping type of each buried injection region is opposite to that of the JFET region. According to the semiconductor structure and the forming method thereof, the buried injection region is formed in the JFET region to serve as an electric field shielding layer, balance of an electric field and current is achieved under the condition that the channel density is not reduced, the process is simple, and continuous miniaturization of the size of the JFET region is not affected.

The semiconductor device of the present invention includes an insulating layer, a high voltage coil and a low voltage coil which are disposed in the insulating layer at an interval in the vertical direction, a low potential portion which is provided in a low voltage region disposed around a high voltage region for the high voltage coil in planar view and is connected with potential lower than the high voltage coil, and an electric field shield portion which is disposed between the high voltage coil and the low voltage region and includes an electrically floated metal member.

The embodiment of the invention discloses a silicon carbide power device cell, a preparation method thereof and a semiconductor device, and belongs to the technical field of semiconductors. The silicon carbide power device cell comprises a substrate; a gate structure disposed in the substrate; the source electrode structure is arranged in the substrate and surrounds at least part of the side surface of the gate electrode structure; the source electrode structure comprises a first source electrode structure and a second source electrode structure, and the first source electrode structure is connected with the second source electrode structure through the source electrode layer; part of the second source structure covers the bottom of the gate structure, and part of the second source structure serves as an electric field shielding structure. According to the invention, the channel area of the device during forward conduction can be increased, and forward conduction resistance is reduced, so that the performance of the device is improved, and the output characteristic of the device is improved.

The SiC MOSFET device is characterized in that a current diffusion layer of a first doping type is arranged between a lightly doped first epitaxial layer of the first doping type and a gate dielectric layer, and a well region of a second doping type, a source region of the first doping type and a contact region of the second doping type are arranged in the current diffusion layer; the bottom end of the well region of the second doping type is provided with a deeply-buried electric field shielding region of the second doping type, which is used for reducing the intensity of an electric field below the Schottky electrode of the source electrode and improving the short-circuit current impact resistance of the device, thereby effectively reducing the intensity of the electric field below the Schottky electrode and improving the short-circuit current impact resistance of the device. The short-circuit tolerance time of the device is prolonged; the shape, width or depth of the deeply-buried electric field shielding area is changed, and the influence of the deeply-buried electric field shielding area on the normal working performance of the device is balanced; a current diffusion layer is additionally arranged to maintain the through-current capability and the voltage endurance capability of the device; the device is simple in structure and preparation method, has high compatibility with a traditional SiC MOSFET preparation process, and is easy for batch production.

The invention discloses an electric field radiation elimination structure and method and an electric heating film without electric field radiation, and relates to the technical field of electric field shielding, the electric field radiation elimination structure comprises an electric field radiation elimination layer, a grounding wire is connected outside the electric field radiation elimination layer, and the outer surface of the electric field radiation elimination layer is coated with an electric field adsorption layer; the electric field adsorption layer is formed by drying MXene complex liquid on the outer surface of the electric field radiation elimination layer; the electric field adsorption layer added on the surface of the electric field radiation elimination layer not only greatly improves the electric field shielding energy efficiency of the electric field radiation elimination layer, but also improves the thermal stability of the electric field shielding energy efficiency of the electric field radiation elimination layer, and meanwhile, the electric field adsorption layer also greatly improves the oxidation resistance of the electric field radiation elimination layer. And the service life of the electric field radiation elimination layer is prolonged.

The invention provides a trench type MOSFET device integrated with a junction control diode and electronic equipment, and relates to the technical field of semiconductor devices. The P-type epitaxial layer, the first P-type masking layer and the second P-type masking layer are grounded, a better electric field shielding effect can be obtained during reverse voltage withstanding, and voltage jump caused by floating of the P-type epitaxial layer, the first P-type masking layer and the second P-type masking layer can be avoided in the switching process, so that degradation of the switching characteristic of the device is avoided. Moreover, a junction-controlled fly-wheel diode region is led out between the two trench MOSFET regions, and the conduction voltage drop of the integrated junction-controlled fly-wheel diode is lower than that of a body diode of the device, so that the conduction of the body diode is shielded; moreover, the junction-controlled fly-wheel diode is a unipolar device, does not have a minority carrier storage effect, is short in reverse recovery time, can reduce the switching loss of the device, and improves the performance of the trench type MOSFET device.

An electromagnetic shielding and heat-conducting multi-layer material and a preparation method thereof. The multi-layer material includes an electric field shielding layer, an epoxy heat-conducting adhesive layer, and a magnetic field shielding layer. The electric field shielding layer includes a copper foil layer with a thickness of 5-12 μm. The magnetic field shielding layer has a thickness of 1-3 mm and includes a resin matrix A and carbon fiber cloth. By weight, the resin matrix A includes: 100 parts of bismaleimide resin, 60-68 parts of 3,3-diallylbisphenol A, 32-40 parts of triallyl isocyanurate, 18-20 parts of N,N-dimethylformamide, 100-160 parts of magnetic field shielding filler, 8-10 parts of di-sec-octyl phthalate, and 0.3-0.8 parts of cobalt naphthenate. The magnetic field shielding filler is compounded by nano-manganese zinc ferrite and micron nickel powder in a mass ratio of (80-120):(30-40). The electromagnetic shielding and heat-conducting multi-layer material of the present invention has both electric field and magnetic field shielding functions and is particularly suitable for high magnetic field and high electric field application environments.

The embodiment of the invention discloses a silicon carbide power device cellular structure, a preparation method thereof and a semiconductor device, and belongs to the technical field of semiconductors. The silicon carbide power device cellular structure comprises a substrate; the gate structure comprises at least two first gate structures, and the at least two first gate structures are arranged in the substrate at intervals; the source electrode structure is arranged on the substrate and at least surrounds partial side surfaces of the two first grid electrode structures; a part of the source structure between the two first gate structures extends towards the bottom surface of the substrate to form a protruding structure, and a part of the protruding structure forms an electric field shielding structure. The gate oxide electric field can be better shielded by adding the source electrode structure, in addition, more carriers can be provided by adding the source electrode structure, the concentration of the source electrode structure can be further reduced by increasing the area, and therefore the anti-short-circuit capacity of the device is properly improved.

The present application discloses an electric field shielding effectiveness measurement method, system and electronic device, which can comprehensively and accurately measure the electric field shielding effectiveness. The method includes: placing the electronic device to be measured in an interference electric field; adjusting the field parameters of the interference electric field and collecting the electric field information of the target analysis area under different field parameters when there is a shielding shell and when there is no shielding shell; calculating and determining the mean field strength of the target analysis area according to the electric field information; calculating and determining the electric field shielding effectiveness according to the ratio of the mean field strength when there is a shielding shell and when there is no shielding shell. The system includes an electric field interference unit, an electric field information collection unit, a field strength mean calculation unit and an electric field shielding effectiveness calculation unit. The electronic device includes a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the electric field shielding effectiveness measurement method when executing the computer program.

The invention relates to a semiconductor device. The semiconductor device comprises a semiconductor material layer; a gate trench and a gate structure, the gate trench extending from the top surface of the semiconductor material layer into the semiconductor material layer; the gate structure is located in the gate trench; the source electrode regions are positioned between the adjacent grid electrode grooves; the source region comprises a well region and a source contact region located above the well region; the anti-punch-through structure is located in the well region, and the doping concentration of the anti-punch-through structure is larger than that of the well region; the first electric field shielding structures are located between the adjacent grid electrode grooves; wherein the depth of the first electric field shielding structure is greater than that of the gate trench. According to the invention, the anti-punch-through structure and the first electric field shielding structure with relatively high doping concentration are arranged, so that the blocking voltage bearing capability of the device under a short channel condition can be remarkably improved, the gate oxide reliability is improved, and the stability and reliability of the device in long-term working can be further improved.

The application relates to the technical field of field effect transistor devices, and discloses a two-dimensional material field effect transistor and a preparation method thereof. The two-dimensional material field effect transistor comprises a substrate insulating layer, a gate layer, a gate contact electrode, a vertical electric field shielding structure, a second insulating layer and a conductive channel film which are arranged in a stack. A second step and a third step are formed on the side of the conductive channel film away from the second insulating layer; the second step and the third step are arranged along the stacking direction. A first contact electrode is formed on the second step surface through oblique angle deposition, and a second contact electrode is formed on the third step surface through oblique angle deposition; the side surface of the first contact electrode facing the third step is aligned with the end of the second step surface facing the third step. The first contact electrode and the second contact electrode are deposited through the oblique angle deposition mode, the dependence on a photoetching device and a overlay process precision in the development process of the existing field effect transistor is reduced, and the channel length and the gate length are simultaneously micronized.

The present invention relates to the field of semiconductor technology, and in particular to a trench-type Schottky diode device, wherein the active region of the device is formed by connecting a plurality of primitive cells in parallel, wherein a basic primitive cell includes a trench and a p+ layer in an orthogonal arrangement, that is, the direction of the trench and the p+ layer is perpendicular; in a primitive cell, along the depth direction perpendicular to the paper surface, there are structure A and structure B in sequence, wherein the structure A is a pure trench Schottky diode structure, and the structure B is a pn diode structure. For n-type conductive devices, the primitive cell of the device of the present invention forms an orthogonal arrangement of the p+ region and the trench by opposite types of doping, thereby realizing electric field shielding of the trench and the Schottky contact, and reducing the reverse bias leakage current of the device. At the same time, through the Schottky contact with different potential barriers in the trench and on the table, the turn-on voltage and on-resistance of the device are reduced.

The present invention relates to an IGBT device with a thyristor structure using self-biased MOS clamping, which can also be regarded as an integrated ETO device. The body region of the IGBT device is composed of multiple layers of P-type doped layers and N-type doped layers arranged alternately, and adjacent doped regions of the same conductive type are completely isolated by another conductive type doped region. The device of the present invention uses a self-biased MOS (Q2) to clamp the electric field shielding layer, so that the external control MOS (Q1, Q2) of the traditional ETO can be monolithically integrated into the device. At the same time, compared with the IGBT with a carrier storage layer, the self-biased MOS (Q2) clamps the drain potential of the MOS (Q1) in the structure of the present invention at a lower level, thereby greatly improving the doping concentration threshold of the carrier storage layer and reducing the on-state voltage drop of the device; and the clamped MOS drain potential can reduce the saturation current of the new structure, thereby increasing the short-circuit safe working area of ​​the new device.

An electric field emission device includes a vacuum vessel configured to include a vacuum chamber; an emitter positioned on one side in an axial direction of the chamber and including an electron generation portion facing another side in the axial direction; a target positioned on the other side of the chamber and facing the emitter; a guard electrode that is a cylindrical body, is fixed to the vacuum vessel, and has an opening portion; a support to move the emitter in the axial direction on an inner side of the guard electrode; and an electric field shield body formed of a conductor connected to the guard electrode. The electric field shield body partially overlaps the opening portion on a projection plane in the axial direction, and is formed in a shape partitioning the opening portion into a plurality of areas.

The present invention discloses an electric field radiation elimination structure, method and electric heating film without electric field radiation, which relate to the field of electric field shielding technology, including an electric field radiation elimination layer, which is externally connected to a grounding wire, and an electric field adsorption layer is coated on the outer surface of the electric field radiation elimination layer, and the electric field adsorption layer is formed by drying a MXene composite liquid on the outer surface of the electric field radiation elimination layer; the electric field adsorption layer added to the surface of the electric field radiation elimination layer not only greatly improves the electric field shielding energy efficiency of the electric field radiation elimination layer, but also improves the thermal stability of the electric field shielding energy efficiency of the electric field radiation elimination layer, and at the same time, the electric field adsorption layer also greatly increases the oxidation resistance of the electric field radiation elimination layer, thereby increasing the service life of the electric field radiation elimination layer.

The embodiment of the utility model relates to a trench gate transistor. The trench gate transistor comprises a semiconductor material layer; the gate trench comprises a side wall and a bottom wall, and the side wall comprises at least two first parts arranged at intervals in the extension direction and a second part located between the two adjacent first parts; the first electric field shielding structure is positioned outside the gate trench and is adjacent to the first part; the body region is located outside the gate trench and adjoins the second part, and the part, close to the gate trench, in the body region is used for forming a channel region; the drift region is positioned below the channel region; the second electric field shielding structures are located below the first electric field shielding structures, and at least part of the second electric field shielding structures extend to the position below the channel region, so that the width of the part, located between every two adjacent second electric field shielding structures, of the drift region is smaller than that of the channel region in the extending direction; therefore, the saturation current of the device is greatly reduced, and the short-circuit performance of the device is optimized; therefore, the specific on-resistance Rsp, the protection effect and the short-circuit performance are considered.

The present application relates to the field of semiconductors, and in particular to a MOSFET device and a manufacturing method therefor. The MOSFET device comprises a semiconductor material layer, a well region, a gate trench, and an electric field shielding structure; the gate trench extends from an upper surface of the semiconductor material layer to the interior of the semiconductor material layer and comprises a first trench portion and a second trench portion; the bottom wall of the first trench portion is located in the well region; the second trench portion passes through the well region and extends into the semiconductor material layer below the well region; the electric field shielding structure comprises a first structure portion and a second structure portion which are electrically connected to each other; the first structure portion is located below the first trench portion and is in electrical contact with the well region; and the second structure portion is located below the second trench portion. According to the embodiments of the present application, the cell pitch is reduced, the stability of long-term operation of a device is improved, and the manufacturing process is simplified.

The present invention specifically relates to a silicon control unit and a wide bandgap semiconductor unit composite device structure and a manufacturing method thereof. The device structure includes a substrate; an epitaxial layer, the epitaxial layer is made on the substrate and the epitaxial layer is a wide bandgap semiconductor material, an electron tunneling layer is made on the upper surface of the epitaxial layer, and the epitaxial layer is divided into a voltage-resistant layer structural region and an electric field shielding structural region; a silicon material layer, the silicon material layer is made on the electron tunneling layer; a switch control unit, the switch control unit is made in the silicon material layer; a shielding region, the shielding region is made in the electric field shielding structural region of the electron tunneling layer and / or the epitaxial layer; a drain electrode, the drain electrode is made on the second surface of the substrate. The present invention provides a silicon control unit and a wide bandgap semiconductor voltage-resistant unit composite device structure, which solves the difficulties in the design, process manufacturing and special equipment requirements of wide bandgap semiconductor devices and obtains a more excellent device performance.

The present application belongs to the technical field of semiconductors. Disclosed are a silicon carbide power device cell structure and a preparation method therefor, and a semiconductor device. A silicon carbide power device comprises a substrate, source structures, a gate structure, and electric-field shielding structures, wherein the gate structure is disposed in the substrate; the source structures are disposed on the substrate and surround at least part of side faces of the gate structure; and the electric-field shielding structures are disposed in the substrate, surround the bottom of the gate structure and are connected to the source structures. The present application can redistribute to the electric-field shielding structures an electric field of a gate dielectric layer of a silicon carbide semiconductor device cell structure in a reverse blocking state, so as to maximize the shielding effect, thereby reducing the electric field of the gate dielectric layer, such that the semiconductor device has high reliability.

The present application relates to the technical field of material mechanical property testing, and proposes an electric field device for testing fiber filament lift, which is used to solve the key problem that the lift characteristics of fiber materials cannot be accurately measured in a dynamic electric field environment in the prior art, and promote its application in aerospace protection, bionic driving and intelligent material design. The device provides a stable and adjustable electric field environment through a modular electric field generating system, provides the electric field force source necessary for the fiber filament to generate lift; the electric field intensity in the electric field generating system is measured by redundantly arranging electric field sensors; the external electromagnetic interference is isolated and the internal electric field is constrained by the electric field shielding shell to prevent leakage, and at the same time, the internal components are protected from dust and debris. Through the collaborative design of the modular electric field generating system, the self-adaptive lifting system and the high-sensitivity sensing technology, the present application realizes the accurate simulation and real-time measurement of the typical electric field of Mars atmosphere (0-20kV / m).

A technique capable of preventing bubbles from being accumulated on a lower surface of an electric field shield plate is provided. A plating apparatus includes: a plating tank in which a plating solution is retained, and an anode is arranged: a substrate holder that is arranged above the anode, and holds a substrate serving as a cathode such that a surface to be plated of the substrate faces the anode; a diaphragm that partitions an inside of the plating tank into an anode region where the anode is arranged, and a cathode region where the substrate is arranged; and a supporting member that is in contact with a lower surface of the diaphragm and supports the diaphragm, and includes a plurality of beam components extending over regions between the anode and the substrate along the lower surface of the diaphragm, the beam components including bubble guide paths for guiding bubbles from the regions between the anode and the substrate to an outside.

The invention discloses a semi-conductive paper-wrapped aluminum cable paper tape structure and an oil-immersed composite voltage transformer, and the structure comprises an inner layer which is disposed at one side of a base layer and is used for uniformizing the distribution of an electric field; the base layer is used for arranging the inner layer and the outer layer; and the outer layer is arranged on the other side of the base layer and is used for structural shaping and electric field shielding. The base layer is used as a base layer for arranging the inner layer and the outer layer, needs to be made of an insulating material (such as cable paper), has certain mechanical strength and can be made into a composite material with the inner layer and the outer layer on the basis of ensuring insulation, the inner layer is used for uniformizing an electric field, and the outer layer forms a Faraday cage to improve the shielding performance and also has certain mechanical strength. In addition, a structure shaping effect is also needed, so that the shielding layer can be made into a plate-shaped shielding layer, and can also be made into a shielding tube as shown in Figure 7.

The application discloses a kind of electric field shielded rotary friction and wear testing machine, comprising: rotary drive device, can drive ring sample mounting rod positive and negative rotation;Ring sample mounting rod, ring sample can be installed;Vertical loading device, can drive block sample mounting table lifting, so that the block sample on block sample mounting table and the ring sample on ring sample mounting rod abut to exert loading force, and adjust the size of loading force;Detection device, between vertical loading device and block sample mounting table, including loading force sensor and two opposite friction force sensors, loading force sensor is used to detect vertical loading force, the axial direction of ring sample mounting rod, the force direction of loading force sensor and friction force sensor is perpendicular;Block sample mounting table, can install block sample;Electric field shielding box, above rack, block sample mounting table and ring sample mounting rod are located in electric field shielding box. To provide a kind of can simultaneously meet the test demand of rotary friction pair and swing friction pair friction and wear testing machine.

The invention relates to the technical field of material mechanical property testing, provides an electric field device for testing fiber filament lift force, and is used for solving the key problem that the lift force characteristic of a fiber material in a dynamic electric field environment cannot be accurately measured in the prior art and promoting the application of the electric field device in spaceflight protection, bionic driving and intelligent material design. According to the device, a stable and adjustable electric field environment is provided through a modularized electric field generation system, and an electric field force source necessary for generating lift force is provided for fiber filaments; measuring the electric field intensity in the electric field generation system by arranging the electric field sensing redundancy; the electric field shielding shell isolates external electromagnetic interference and restrains an internal electric field, leakage of the internal electric field is prevented, and meanwhile internal components are protected against influences of dust and sundries. Through collaborative design of the modular electric field generation system, the self-adaptive lifting system and the high-sensitivity sensing technology, accurate simulation and real-time measurement of the typical electric field (0-20 kV / m) of the Mars atmosphere are realized.

The application discloses a display panel and a display device, relates to the technical field of display, and further relates to an array substrate, a color film substrate, an electric field shielding layer, a shielding electric field insulating layer and a data line arrangement layer. The color film substrate is not provided with a black matrix corresponding to the data line on the side of the array substrate. The electric field shielding layer comprises a plurality of shielding electrodes. The orthographic projection of each shielding electrode on the substrate covers the orthographic projection of each data line on the array substrate body. The shielding electric field insulating layer comprises a first insulating part, a second insulating part and a third insulating part which are sequentially connected. The second insulating part is arranged corresponding to the shielding electrode. The thickness of the second insulating part is greater than the thickness of the first insulating part and the thickness of the third insulating part. The application reduces the pressure difference and improves the transmittance through the above design.

The embodiment of the invention provides a trench MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device, a manufacturing method and a chip. The device comprises a first section region, a second section region and a third section region which are alternately arranged along a first direction, each of the first section region, the second section region and the third section region comprises an N-type substrate, an epitaxial layer, a first groove, an oxide layer, a first N region, a P well region, an N + region, a second groove, a grid electrode and a source electrode; the epitaxial layer is arranged on one side of the N-type substrate; the first N region is located below the two sides of the first groove; the N + regions are located on the two sides of the first groove. The P well region is connected below the N + region; the second groove is located at the bottom of the first groove; the P regions, located at the bottom and corners of the second groove, of the first section region play a role in electric field shielding, and the P regions, located at the bottom of the first groove, of the third section region play a role in electric field shielding, so that device damage caused by a relatively strong electric field generated at the corners of the grooves is avoided, and the reliability of the device is improved.

The invention discloses an alkali metal atom gas chamber based on Rydberg electric field measurement and an electric field measurement device. The problem of electric field shielding during electric field measurement is solved. According to the invention, the square glass with high purity and low conductivity is selected as the air chamber main body, so that the air chamber main body has good optical transparency and chemical stability. By selecting metal with high conductivity and low resistivity, effective transmission of inductive charge signals is ensured. Glass and metal are subjected to laser welding, so that no air leakage is ensured. The atom gas chamber is firstly vacuumized, then alkali metal atoms are injected, and stable atom steam is formed. The Rydberg atomic glass gas chamber is simple in structure, interference of an external stray electric field is reduced, measurement stability is improved, the shielding effect of a traditional Rydberg atomic glass gas chamber in low-frequency electric field measurement is effectively overcome through a unique metal-glass composite structure, and sensitivity and accuracy of electric field measurement are improved.

The adjustable high-voltage polar plate array device comprises an insulating barrier plate and a plurality of high-voltage polar plates which are sequentially arranged at intervals in the front-back direction, the insulating barrier plate comprises a bottom plate, a left side plate and a right side plate, the left side plate and the right side plate extend from the bottom plate to the same side, and conductive sliding grooves extending in the front-back direction are fixedly formed in the left side plate and the right side plate respectively; the left end and the right end of the high-voltage polar plate extend into the conductive sliding grooves respectively, and the left end and the right end of the high-voltage polar plate are in sliding connection with the conductive sliding grooves respectively. According to the invention, the high-voltage polar plate is directly inserted and fixed in the conductive chute in the insulating barrier plate, the assembly structure is simple, the contact is tight, the stable formation of an electric field is facilitated, and meanwhile, a good electric field shielding effect and relatively high safety are achieved; the distance between the high-voltage polar plates can be adjusted according to the particle sizes and physiological characteristics of different forage grass seeds, so that the seeds are subjected to uniform and stable electric field action in the treatment process, and the reliability and consistency of the treatment effect are improved.

The invention relates to the technical field of field effect transistor devices, and discloses a two-dimensional material field effect transistor and a preparation method thereof. The two-dimensional material field effect transistor comprises a substrate insulating layer, a gate layer, a gate contact electrode, a vertical electric field shielding structure, a second insulating layer and a conductive channel film which are arranged in a stacked mode. A second step and a third step are formed on one side, far away from the second insulating layer, of the conductive channel film; the second step and the third step are arranged in the stacking direction. Forming a first contact electrode on the second step surface through oblique angle deposition, and forming a second contact electrode on the third step surface through oblique angle deposition; one side surface of the first contact electrode facing the third step is aligned with one end of the second step surface facing the third step. The first contact electrode and the second contact electrode are deposited in an oblique angle deposition mode, the dependence on photoetching equipment and overlay process precision in the development process of an existing field effect transistor is reduced, and synchronous miniaturization of the channel length and the grid electrode length is achieved.