阅读说明：本技术 一种电流孔径垂直电子晶体管外延结构及其制备方法 (Current aperture vertical electronic transistor epitaxial structure and preparation method thereof ) 是由 左万胜 钮应喜 程海英 钟敏 郗修臻 张晓洪 刘锦锦 刘洋 史田超 于 2019-12-10 设计创作，主要内容包括：本发明公开了一种电流孔径垂直电子晶体管外延结构及其制备方法,所述电流孔径垂直电子晶体管外延结构由下至上依次包括：GaN自支撑衬底或硅基衬底、低掺杂n型GaN漂移层A、多周期GaN/Al<Sub>x</Sub>Ga<Sub>1-x</Sub>N隧穿层,其中0<x<0.3、低掺杂n型GaN漂移层B、导通孔径层、GaN沟道层；并且在所述导通孔径层的两侧还分别设有电流阻挡层；通过在漂移区内插入多周期GaN/Al<Sub>x</Sub>Ga<Sub>1-x</Sub>N隧穿层,通过调控多周期的周期数、多周期内的GaN与Al<Sub>X</Sub>Ga<Sub>1-X</Sub>N的厚度及Al组分,提高器件的耐压特性,通过隧穿效应显著缓解器件击穿电压与导通电阻之间的矛盾,改善器件的稳定性和可靠性。(The invention discloses a current aperture vertical electronic transistor epitaxial structure and a preparation method thereof, wherein the current aperture vertical electronic transistor epitaxial structure sequentially comprises the following components from bottom to top: GaN self-supporting substrate or silicon-based substrate, low-doped n-type GaN drift layer A, and multicycle GaN/Al x Ga 1‑x N a tunneling layer of which 0<x<0.3, a low-doped n-type GaN drift layer B, a conduction aperture layer and a GaN channel layer; current blocking layers are respectively arranged on two sides of the conducting aperture layer; by inserting multi-period GaN/Al in the drift region x Ga 1‑x N tunneling layer by adjusting and controlling the periodicity of multiple periods, GaN and Al in multiple periods X Ga 1‑X The thickness of N and the Al component improve the voltage resistance of the device, and the breakdown voltage and the on-resistance of the device are remarkably relieved through the tunneling effectThe contradiction between the two methods improves the stability and the reliability of the device.)

1. The utility model provides a vertical electron transistor epitaxial structure in current aperture which characterized in that, the vertical electron transistor epitaxial structure in current aperture includes by lower supreme in proper order: GaN self-supporting substrate or silicon-based substrate, low-doped n-type GaN drift layer A, and multicycle GaN/Al_xGa_1-xN a tunneling layer of which 0<x<0.3, a low-doped n-type GaN drift layer B, a conduction aperture layer and a GaN channel layer; and current blocking layers are respectively arranged on two sides of the conducting aperture layer.

2. The current aperture vertical electron transistor epitaxial structure of claim 1, wherein the low doped n-type GaN semiconductor material forming the low doped n-type GaN drift layer a, the low doped n-type GaN drift layer B are each silicon doped n-type GaN semiconductor material.

3. The current aperture vertical electronic transistor epitaxial structure of claim 2, wherein the amount of silicon doping in the lowly doped n-type GaN drift layer B is 10-100 times the amount of silicon doping in the lowly doped n-type GaN drift layer a.

4. The current aperture vertical electronic transistor epitaxial structure of claim 2 or 3, wherein the amount of silicon doping in the lightly doped n-type GaN drift layer A and the lightly doped n-type GaN drift layer B is 1 x 10¹⁵～5×10¹⁵cm^-3，1×10¹⁶～5×10¹⁷cm^-3。

5. The vertical electron transistor epitaxial structure of current aperture according to any of claims 1-3, characterized in that the thickness of the lightly doped n-type GaN drift layer A and the lightly doped n-type GaN drift layer B are 1-2 μm and 2-3 μm respectively.

6. The current aperture vertical electron transistor epitaxial structure of claim 1, wherein the multicycle GaN/Al_xGa_1-xThe number of cycles of the N tunneling layers is 3-5.

7. The current aperture vertical electron transistor epitaxial structure of claim 1 or 6, wherein the multicycle GaN/Al_xGa_1-xIn the N tunneling layer, the thickness of GaN is 1-1.5nm, and Al_xGa_1-xThe thickness of N is 1-2 nm.

8. The current aperture vertical electron transistor epitaxial structure of claim 1, wherein the conducting aperture layer is formed of n-type GaN semiconductor material, the n-type doping concentration in the conducting aperture layer being greater than the n-type doping concentration in the low doped n-type GaN drift layer B.

9. A method for preparing a current aperture vertical electron transistor epitaxial structure according to any of claims 1 to 8, characterized in that the method comprises the following steps:

(1) extending a low-doped n-type GaN layer semiconductor material on a substrate to form a low-doped n-type GaN drift layer A;

(2) epitaxial multicycle GaN/Al on low doped n-type GaN drift layer A_xGa_1-xAn N tunneling layer;

(3) in multicycle GaN/Al_xGa_1-xA low-doped N-type GaN drift layer B is extended on the N tunneling layer;

(4) extending an n-type GaN semiconductor material on the low-doped n-type GaN drift layer B to form a conducting aperture layer with the thickness of 0.5-1 mu m;

(5) manufacturing a mask on the conducting aperture layer, and injecting p-type impurity Al into the positions on two sides of the conducting aperture layer by using the mask to form a current blocking layer with the thickness being the same as that of the conducting aperture layer and the width being 0.5-1 mu m;

(6) and (3) extending GaN semiconductor materials on the upper parts of the current blocking layer and the conducting aperture layer to form a GaN channel layer with the thickness of 50-200 nm.

10. The method as claimed in claim 9, wherein the temperature and pressure for epitaxial growth in steps (1) and (3) are 1150-;

in the step (2), the temperature and pressure of epitaxial growth are 1050-;

in the steps (4) and (6), the temperature and pressure of epitaxial growth are 1100 ℃ and 1120 ℃ and 100 ℃ and 200Torr, respectively.

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to a current aperture vertical electronic transistor epitaxial structure and a preparation method thereof.

Background

Horizontal structure AlGaN/GaN HEMTs have been developed to date from 1993, and the low on-resistance and energy loss of devices is facilitated by the presence of a high concentration of 2DEG at the AlGaN/GaN heterojunction interface. The AlGaN/GaN HEMT with the horizontal structure bears high withstand voltage under the off state, a large amount of charges are accumulated on the grid close to the edge of a drain electrode, avalanche breakdown easily occurs when a device works under the high-voltage state under the electric field concentration effect, and electrons are easily bound on the surface state of AlGaN to cause current collapse.

The AlGaN/GaN current aperture vertical electronic transistor with the vertical structure is in an off state, and the n-GaN drift region bears most of voltage. The current flows through the drift region to the drain electrode along the vertical direction, and the low doping concentration of the n-GaN can increase the breakdown voltage of the device but can increase the on-resistance of the device. The voltage resistance of the prior art device is improved by reducing the doping concentration of the buffer layer and increasing the on-resistance. How to obtain low-doping and high-mobility n-GaN is an urgent problem to be solved for improving the withstand voltage of the device and reducing the on-resistance.

Disclosure of Invention

The invention aims to provide a current aperture vertical electronic transistor epitaxial structure and a preparation method thereof.

The technical scheme adopted by the invention is as follows:

the utility model provides a vertical electron transistor epitaxial structure of current aperture, the vertical electron transistor epitaxial structure of current aperture includes by lower supreme in proper order: GaN self-supporting substrate or silicon-based substrate, low-doped n-type GaN drift layer A, and multicycle GaN/Al_xGa_1-xN a tunneling layer of which 0<x<0.3, a low-doped n-type GaN drift layer B, a conduction aperture layer and a GaN channel layer; and current blocking layers are respectively arranged on two sides of the conducting aperture layer.

Further, a barrier layer is also included on the GaN channel layer.

The low-doped n-type GaN semiconductor materials for forming the low-doped n-type GaN drift layer A and the low-doped n-type GaN drift layer B are all silicon-doped n-type GaN semiconductor materials.

The doping amount of silicon in the low-doped n-type GaN drift layer B is 10-100 times of that of silicon in the low-doped n-type GaN drift layer A, and the structure can remarkably relieve the contradiction between the breakdown voltage and the on-resistance of the device through a tunneling effect.

The doping amount of silicon in the low-doped n-type GaN drift layer A and the low-doped n-type GaN drift layer B is respectively 1 multiplied by 10¹⁵～5×10¹⁵cm^-3，1×10¹⁶～5×10¹⁷cm^-3。

The thicknesses of the low-doped n-type GaN drift layer A and the low-doped n-type GaN drift layer B are 1-2 micrometers and 2-3 micrometers respectively.

The multicycle GaN/Al_xGa_1-xThe number of cycles of the N tunneling layers is 3-5. The multicycle GaN/Al_xGa_1-xIn the N tunneling layer, the thickness of GaN is 1-1.5nm, and Al_xGa_1-xThe thickness of N is 1-2 nm; carriers are difficult to pass by means of tunneling above this period; when the barrier is sufficiently thin, carriers with energy lower than the barrier can form a current through the barrier, with SiH₄Increase of doping concentration, potential barrierThe thinner the carrier tunneling probability is larger, and the voltage resistance of the device is in direct proportion to the components of the tunneling layer Al and the whole thickness of the tunneling layer, so that the voltage resistance is reduced below the period, and the invention passes through the multi-period GaN/Al_xGa_1-xThe N tunneling layer has a good tunneling effect due to the number of cycles and the thickness.

The conducting aperture layer is formed by an n-type GaN semiconductor material, and in order to increase the conductivity, the n-type doping concentration in the conducting aperture layer is larger than that in the low-doped n-type GaN drift layer B.

The invention also provides a preparation method of the epitaxial structure of the current aperture vertical electronic transistor, which comprises the following steps:

(1) extending a low-doped n-type GaN layer semiconductor material on a GaN self-supporting substrate or a silicon-based substrate to form a low-doped n-type GaN drift layer A;

(2) epitaxial multicycle GaN/Al on low doped n-type GaN drift layer A_xGa_1-xAn N tunneling layer;

(3) in multicycle GaN/Al_xGa_1-xA low-doped N-type GaN drift layer B is extended on the N tunneling layer;

(4) extending an n-type GaN semiconductor material on the low-doped n-type GaN drift layer B to form a conducting aperture layer with the thickness of 0.5-1 mu m;

(5) manufacturing a mask on the conducting aperture layer, and injecting p-type impurity Al into the positions on two sides of the conducting aperture layer by using the mask to form a current blocking layer with the thickness being the same as that of the conducting aperture layer and the width being 0.5-1 mu m;

(6) and (3) extending GaN semiconductor materials on the upper parts of the current blocking layer and the conducting aperture layer to form a GaN channel layer with the thickness of 50-200 nm.

In the steps (1) and (3), the temperature and pressure of epitaxial growth are 1150-;

in the step (2), the temperature and pressure of epitaxial growth are 1050-;

in the steps (4) and (6), the temperature and pressure of epitaxial growth are 1100 ℃ and 1120 ℃ and 100 ℃ and 200Torr, respectively.

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

1. inserting multi-period GaN/Al in drift region_xGa_1-xN tunneling layer by adjusting and controlling the periodicity of multiple periods, GaN and Al in multiple periods_xGa_1-xThe thickness of N and the Al component improve the voltage resistance of the device, remarkably relieve the contradiction between the breakdown voltage and the on-resistance of the device through the tunneling effect, and improve the stability and the reliability of the device.

2. Compared with the traditional epitaxial structure, the high voltage-resistant characteristic is realized without increasing the thickness of the drift layer, and the consumption of raw materials is reduced.

Drawings

FIG. 1 is a view showing an epitaxial structure of a current aperture vertical electron transistor in example 1;

FIG. 2 is a view showing an epitaxial structure of an electronic transistor in comparative example 1;

FIG. 3 is an I-V curve of the epitaxial structure of the electronic transistor in the examples and comparative examples after the electronic transistor device was fabricated;

wherein, the 1-GaN self-supporting substrate or the silicon-based substrate, the 2-low doped n-type GaN drift layer A, and the 3-multicycle GaN/Al_xGa_1-xThe GaN-based LED chip comprises an N tunneling layer, a 4-low-doped N-type GaN drift layer B, a 5-conduction aperture layer, a 6-GaN channel layer and a 7-current blocking layer.

Detailed Description

The present invention will be described in detail with reference to examples.