CN208985988U - A kind of groove type MOS-HEMT - Google Patents

Abstract

The utility model discloses a kind of groove type MOS-HEMT, including substrate, buffer layer, GaN layer and the N-AlGaN layer being cascading from bottom to up, the GaN layer and the N-AlGaN layers of formation hetero-junctions, one end of the upper surface N-AlGaN layers of is equipped with source electrode, the other end has drain electrode, the source electrode and the drain electrode and N-AlGaN layers of formation Ohmic contact；The upper surface N-AlGaN layers of has been sequentially overlapped the first N-GaN layers, AlN layers, the 2nd N-GaN layers and dielectric layer from bottom to top, the dielectric layer has groove, the groove sequentially pass through the described first N-GaN layers, AlN layers, the 2nd N-GaN layers extend to N-AlGaN layers described, be provided with gate electrode in the groove.The utility model prevents gate electrode to be laterally tunnelled to source electrode and drain electrode tunnel current and tunnel current in downward direction by the dielectric layer of groove type, and triple protection improve the stability of component to reduce component power dissipation.

Description

A kind of groove type MOS-HEMT

Technical field

The utility model relates to the high electron mobility transistor field (HEMT) more particularly to a kind of groove type MOS- HEMT。

Background technique

High electron mobility transistor (High electron mobility transistor, HEMT), also referred to as modulation is mixed Miscellaneous field-effect tube (modulation-doped FET, MODFET) is one kind of field effect transistor, it is had not using two kinds Material with energy gap forms heterojunction structure, provides channel for carrier.And the GaN high electron mobility crystal developed in recent years Guan Ze has attracted a large amount of concerns by its good high frequency characteristics.High electron mobility transistor can work under extremely high frequency, Therefore it is widely used in mobile phone, satellite television and radar.

AlGaN/GaN high electron mobility transistor (HEMT) has high-frequency, high-temperature operation, high power, wide energy gap, height Electric field, high thermal conductivity, the characteristic of high electron saturation velocities and high Two-dimensional electron cloud concentration, two-dimensional electron gas (Two- Dimensional electron gas, 2DEG) refer to electron gas can freely in moving in two dimensional directions, and in the third dimension by To the phenomenon that limitation.III nitride heterostructure has biggish spontaneous polarization and piezoelectric effect, this heterojunction structure edge Polar orientation growth, triangular quantum well, that is, Two-dimensional electron cloud (2DEG) are formed on the interface of AlGaN/GaN.It It is the basis of many fieldtrons (such as MOSFET, HEMT) work.GaN high electron mobility transistor can be applied In power switch, high-frequency, the application of high current operation.

But there are the tunneling (Fowler-Nordheim of F-N for existing AlGaN/GaN high electron mobility transistor (HEMT) Tunneling) phenomenon-electronics is easy from the conductive strips that the surface of silicon or gate metal is tunnelled to oxide layer, forms grid leakage Electric current；When especially film thickness is below several nanometers, the probability penetrated will increase.Another directly tunneling (direct Tunneling) the phenomenon that be it is miniature with size of components so that oxidated layer thickness (gate oxide thickness) Become thin, when thickness of grid oxide layer is less than 4nm, on the component of a thin oxide layer, one biggish grid of application is inclined Vg is pressed, therefore whether positive voltage or negative voltage, the electronics for being all easy will cause substrate (or metal electrode) are directly tunnelled to The conductive strips of metal electrode (or substrate) form grid leakage current, and then increase component power dissipation and reduce the stabilization of component Property.

Utility model content

The utility model is intended to solve at least some of the technical problems in related technologies.For this purpose, this reality It is to provide a kind of HEMT of anti-grid leakage current that stability is good with a novel purpose.

The technical scheme adopted by the utility model is a kind of groove type MOS-HEMT, including stack gradually from bottom to up Substrate, buffer layer, GaN layer and the N-AlGaN layer of setting, the GaN layer and the N-AlGaN layers of formation hetero-junctions, it is described One end of N-AlGaN layers of upper surface is equipped with source electrode, and the other end has drain electrode, the source electrode and the drain electrode and N- AlGaN layer forms Ohmic contact；The upper surface N-AlGaN layers of be sequentially overlapped from bottom to top the first N-GaN layers, AlN layers, 2nd N-GaN layers and dielectric layer, the dielectric layer have groove, and the groove sequentially passes through the described first N-GaN layers, AlN Layer, the 2nd N-GaN layers extend to N-AlGaN layers described, be provided with gate electrode in the groove.

Further, the dielectric layer is High-k material.

Further, the material of the dielectric layer is HfO₂、MgO、TiO₂、Ga₂O₃, spun-on dielectric, topological insulator In any one.

Further, the dielectric layer is formed using atomic layer deposition.

Further, the material of the buffer layer is AlN or low temperature GaN.

Further, the thickness of the AlGaN layer is less than 25nm.

The beneficial effects of the utility model are: by the dielectric layer of groove type prevent gate electrode be laterally tunnelled to source electrode and Drain electrode tunnel current and tunnel current in downward direction, triple protection improve component to reduce component power dissipation Stability.

Detailed description of the invention

Fig. 1 is the facade view of the utility model.

Specific embodiment

It should be noted that in the absence of conflict, the features in the embodiments and the embodiments of the present application can phase Mutually combination.

As shown in Figure 1, a kind of groove type MOS-HEMT, including be cascading from bottom to up substrate 1, buffer layer 2, GaN layer 3 and N-AlGaN layer 4, the GaN layer 3 and N-AlGaN layer 4 form hetero-junctions, form triangular quantum well, It is exactly Two-dimensional electron cloud (2DEG), the one end on 4 upper layer of N-AlGaN layer is equipped with source electrode 6, and the other end has drain electrode 5, institute It states source electrode 6 and the drain electrode 6 and N-AlGaN layer 4 forms Ohmic contact；4 upper surface of N-AlGaN layer is from bottom to top It is sequentially overlapped the first N-GaN layer 7, AlN layer 8, the 2nd N-GaN layer 9 and dielectric layer 10, the dielectric layer 10 has groove 12, the groove 12 sequentially pass through the first N-GaN layer 7, AlN layer 8, the 2nd N-GaN layer 9 extend to it is N-AlGaN layers described 4, gate electrode 11 is provided in the groove 14.Preferably, the material of the buffer layer 2 is AlN or low temperature The thickness of GaN, the N-AlGaN layer 4 are less than 25nm.

The GaN layer 3 at 4 interface of GaN layer 3 and N-AlGaN layer is increased in 7 top addition AlN layer 8 of the first N-GaN layer The density of the electric charge carrier in two-dimensional electron gas on side.In GaN HEMT transistor, high electron density makes to design nature Adapt to higher power output.Electric current flowing can be prevented in the case where no negative voltage.The first N-GaN being sequentially overlapped Layer 7, AlN layer 8,9 three-decker of the 2nd N-GaN layer, can improve surface roughness, while improving output and reliability. Additionally by the dielectric layer 10 of groove type structure prevent gate electrode 11 laterally be tunnelled to source electrode 6 and 5 tunnel current of drain electrode with And tunnel current in downward direction, triple protection improve the stability of component to reduce component power dissipation.

As preferred embodiment, in the present solution, the material of dielectric layer 10 can be HfO₂、MgO、TiO₂、Ga₂O₃, rotation One of painting formula dielectric material or topological insulator.Dielectric layer 10 is that High-k material usually works as reference point, K with air Value is 1.So K value is higher, suppressor grid electronics is directly tunnelled to the conductive strips of metal electrode (or substrate), prevents electric leakage of the grid The ability of stream is stronger, and then reduces component power dissipation and improve the stability of component, and transistor is correctly switched In " open " or " pass " state.

(1) dielectric layer can effectively reduce oxide skin(coating) and GaN trap density, MOS- using magnesia MgO oxide skin(coating) HEMT is compared with traditional HEMT, relatively low in the part of component collapse electric current, also can reduce between source electrode and drain Leakage current and surface trap improve direct current and radiofrequency characteristics.

(2) titanium oxide TiO₂Physics with that chemical stability is good, oxidability is strong, cost cheaply obtains is easy and nontoxic etc. Advantage, therefore other high dielectric materials are compared, with TiO₂Application and research it is relatively broad.

(3) dielectric layer uses ultra-thin HfO₂(3nm)/Al₂O₃The stack architecture of (2nm) hafnium oxide/aluminum oxide, Can reach has to minimum galvanic current collapse and grid leakage current.It is close to increase capacitor to can be a very effective method Degree.With traditional HEMT structure and increase HfO₂Dielectric layer HEMT compares, and only grow up Al on traditional structure₂O₃(Fang Jie under the gate Electric layer) and structure-improved with HfO₂And Al₂O₃Storehouse growth, the two compare, characteristically.Structure-improved has best BV_GDIt (collapses Burst voltage) &V_ONNumerical value promotes I_dsElectric current, because gate dielectric stack architecture can effectively reduce surface defect and surface is let out Leakage current passes through, therefore in Al₂O₃Upper growth HfO₂Method, wherein Al₂O₃Form good protective layer, and HfO₂It can be into one Step inhibits the carrier injected from grid channel with thermionic emission and tunneling behavior

(4) dielectric layer uses spun-on dielectric (spin on dielectrics), and can reach has to minimum electricity Stream collapse and grid leakage current simultaneously save cost.

(5) dielectric layer uses the Ga of electron-beam-evaporated (electron beam evaporation plating)₂O₃, can also arrange in pairs or groups makes Use Al₂O₃ /Ga₂O₃Stack architecture, which reaches, to be had to minimum galvanic current collapse and grid leakage current.

High dielectric constant oxide layer can not be grown up by silicon substrate directly thermal oxidation, therefore production method determines dielectric layer Quality and property.As preferred embodiment, the dielectric layer 9 is formed using atomic layer deposition, by High-k material with list Atom form membrane in layer be plated in substrate surface, the chemical reaction of new one layer of atomic film is that directly preceding layer is associated therewith , this mode makes each reaction only deposit one layer of atom.

It is further used as preferred embodiment, the substrate of substrate 1 may be selected that silicon carbide (SiC) or silicon can also be used (Si) or other can be with the substrate (substrate) of the gallium nitride of epitaxy growth high quality.

It is to be illustrated to the preferable implementation of the utility model, but the utility model creation is not limited to institute above Embodiment is stated, those skilled in the art can also make various be equal without departing from the spirit of the present invention Deformation or replacement, these equivalent deformations or replacement are all included in the scope defined by the claims of the present application.

Claims (6)

1. a kind of groove type MOS-HEMT, which is characterized in that including the substrate, buffer layer, GaN being cascading from bottom to up Layer and N-AlGaN layers, the GaN layer and the N-AlGaN layers of formation hetero-junctions, one end of the upper surface N-AlGaN layers of Equipped with source electrode, the other end has drain electrode, the source electrode and the drain electrode and N-AlGaN layers of formation Ohmic contact；Institute It states N-AlGaN layers of upper surface and has been sequentially overlapped the first N-GaN layers, AlN layers, the 2nd N-GaN layers and dielectric layer, institute from bottom to top Electric layer is given an account of with groove, the groove sequentially pass through the described first N-GaN layer, AlN layers, the 2nd N-GaN layers extend to described in N-AlGaN layers, gate electrode is provided in the groove.

2. groove type MOS-HEMT according to claim 1, which is characterized in that the dielectric layer is High-k material.

3. groove type MOS-HEMT according to claim 2, which is characterized in that the material of the dielectric layer is HfO₂、MgO、 TiO₂、Ga₂O₃, spun-on dielectric, any one in topological insulator.

4. groove type MOS-HEMT according to any one of claims 1 to 3, which is characterized in that the dielectric layer uses former Sublayer deposits to be formed.

5. groove type MOS-HEMT according to claim 4, which is characterized in that the material of the buffer layer is AlN or low temperature GaN。

6. groove type MOS-HEMT according to claim 4, which is characterized in that the thickness of the AlGaN layer is less than 25nm.