CN113764554B - Light-emitting diode based on Si nanowire high-concentration p-type layer and its preparation method - Google Patents

Abstract

The invention discloses a light-emitting diode based on a Si nanowire high-concentration p-type layer and a preparation method thereof, wherein the light-emitting diode comprises the following components from bottom to top: c-plane sapphire substrate 1, high-temperature AlN nucleation layer 2, unintended doped GaN layer 3, n-type GaN layer 4, al _w Ga _1‑w N/Al _x Ga _{1‑ x} N multiple quantum well 5, al _y Ga _1‑y N electron blocking layer 6, high concentration p-type layer 7, p-type Al _z Ga _1‑z An N-type electrode 10 is arranged on one side of the upper part of the N-type GaN layer 4, and the high-concentration p-type layer 7 comprises a p-type Si nanowire structure which comprises a plurality of uniformly arranged p-type Si nanowires. The invention can increase the hole concentration in the p-type layer, thereby improving the hole injection efficiency, improving the luminous efficiency of the device and relieving the droop effect.

Description

Light-emitting diode based on Si nanowire high-concentration p-type layer and its preparation method

technical field

The invention belongs to the technical field of microelectronics, and in particular relates to a light-emitting diode based on a high-concentration p-type layer of Si nanowires and a preparation method.

Background technique

As a commonly used electronic device, light-emitting diode (LED) is commonly prepared by alloying GaN and AlN, and AlGaN-based light-emitting diodes can cover almost the entire ultraviolet spectral range (210-400nm), so that ultraviolet light-emitting diodes are perfectly Suitable for a wide range of applications such as biological, environmental, industrial or medical. However, DUV LEDs still exhibit relatively low luminous efficiency.

For ultraviolet and deep ultraviolet LEDs, the hole injection efficiency of the p-type AlGaN layer is an important factor affecting the luminous efficiency of the diode. One of the main methods to improve the hole injection efficiency is to increase the hole concentration of the p-type layer of the diode. Therefore, how to improve the hole injection efficiency of the p-type AlGaN layer, that is, the hole concentration of the p-type AlGaN layer, has become a technical problem in the field of ultraviolet and deep ultraviolet optoelectronic devices.

The p-type layer of common ultraviolet and deep ultraviolet light-emitting diodes is usually made of AlGaN material uniformly doped with Mg. However, due to this method, the ionization rate of Mg in the p-type layer is low, and the hole concentration is low, so that the hole injection efficiency is low, so that the prepared light-emitting diode has a low luminous efficiency.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention provides a light-emitting diode based on a high-concentration p-type layer of Si nanowires and a preparation method thereof. The technical problem to be solved in the present invention is realized through the following technical solutions:

A light-emitting diode based on a high-concentration p-type layer of Si nanowires provided by the present invention includes from bottom to top: a c-plane sapphire substrate 1, a high-temperature AlN nucleation layer 2, an unintentionally doped GaN layer 3, and an n-type GaN Layer 4, Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5, A _y Ga _1-y N electron blocking layer 6, high-concentration p-type layer 7, p-type Al _z Ga _1-z N layer 8 and p-type electrode 9, one side of n-type GaN layer 4 upper part is provided with n-type electrode 10, n-type electrode 10 and _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum well 5 Arranged adjacently, the high-concentration p-type layer 7 contains a p-type Si nanowire structure, and the p-type Si nanowire structure includes a plurality of uniformly arranged p-type Si nanowires.

Optionally, the high-concentration p-type layer 7 is composed of a p-type Al _z Ga _1-z N layer and a p-type Si nanowire structure uniformly etched out of grooves, and the p-type Si nanowire structure is included in each concave The p-type Si nanowire formed by growing p-type Si in the groove, the thickness of the high-concentration p-type layer is 100-200nm, the length of the p-type Si nanowire is 50-100nm, and the diameter is 5-10nm, p-type Al _z Ga _{1 -z} The adjustment range of the z content in the N layer is 0.1-0.5.

Optionally, the thickness of the high-temperature AlN nucleation layer 2 is 25-45nm; the thickness of the unintentionally doped GaN layer 3 is 1000-3000nm; the thickness of the n-type GaN layer 4 is 1000-3000nm; Al _y Ga _1-y N The thickness of the electron blocking layer 6 is 50nm, and the adjustment range of y is 0.25-0.65; the thickness of the p-type Al _z Ga _1-z N layer 8 is 100nm-200nm, and the adjustment range of z content is 0.1-0.5.

Optionally, the _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum well 5 includes multiple periodic single-layer _{AlwGa1 -wN} well layers and _{AlxGa1 - xN} barrier layers, each The thicknesses of single-layer Al _w Ga _1-w N well layer and Al _x Ga _1-x N barrier layer are 10-30nm and 40-60nm respectively, and the adjustment ranges of Al content w and x are 0.1-0.5 and 0.2-0.6.

In the second aspect, a method for preparing a light-emitting diode based on a high-concentration p-type layer of Si nanowires provided by the present invention includes:

Step 1: obtaining a substrate for preparing a light-emitting diode;

Step 2: heating and high-temperature nitriding treatment on the substrate to obtain the substrate after high-temperature nitriding;

Step 3: Using the MOCVD process, put the substrate into the MOCVD reaction chamber, and sequentially generate a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer from bottom to top;

Step 4: growing 10 periods of Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum wells on the n-type GaN layer;

Among them, the thickness of the single-layer Al _w Ga _1-w N well layer of each period is 10-30nm, the thickness of the Al _x Ga _1-x N barrier layer is 40-60nm respectively, and the adjustment range of the Al content w is 0.1-0.5, The adjustment range of Al content x is 0.2-0.6 respectively;

Step 5: growing an Al _y Ga _{1-y N electron blocking layer with a thickness of 50 nm on the Al w Ga 1-w N /} Al x Ga 1 _{- x} N multiple quantum well;

Among them, the adjustment range of y is 0.25-0.65;

Step 6: growing a p-type Al _z Ga 1 _-z N layer on the A _y Ga _1-y N electron blocking layer;

Among them, the adjustment range of z is 0.1-0.5;

Step 7: Etching away part of the p-type Al _z Ga _1-z N layer on the p-type Al _z Ga _1-z N layer to form a plurality of uniformly arranged grooves with a length of 50-100 nm and a diameter of 5-10 nm;

Step 8: growing p-type Si in the groove to form p-type Si nanowires to obtain a high-concentration p-type layer;

Step 9: growing a p-type _{AlzGa1 -zN} layer on the high-concentration p-type layer;

Step 10: On the n-type GaN layer, deposit an n-type electrode at a position spaced from the Al _w Ga _1-w N/Al _x Ga _1-x N multiquantum well, and deposit on the p-type Al _z Ga _1-z N The p-type electrode completes the fabrication of the light-emitting diode.

Optionally, step 3 includes:

The adopted MOCVD process keeps the reaction chamber at a pressure of 20 Torr-60 Torr, a temperature of 950°C-1150°C, an ammonia gas with a flow rate of 3000sccm-4000sccm and an aluminum source with a flow rate of 30sccm-50sccm. A high-temperature AlN nucleation layer with a thickness of 25-45nm is grown on the bottom;

The pressure of the reaction chamber is kept at 30 Torr-60 Torr, the temperature is 950°C-1150°C, the ammonia gas with the flow rate of 2500sccm-3500sccm and the gallium source with the flow rate of 150sccm-170sccm are fed to grow the high-temperature AlN nucleation layer with a thickness of 1000- 3000nm unintentionally doped GaN layer;

The reaction chamber is maintained at a pressure of 20 Torr-50 Torr, a temperature of 1200°C-1300°C, ammonia gas with a flow rate of 2000sccm-3500sccm, a gallium source with a flow rate of 150sccm-250sccm, and a silicon source with a flow rate of 30sccm-50sccm. n-type GaN with a thickness of 1000-3000 nm is grown on the doped GaN layer.

Optionally, step 4 includes:

The adopted MOCVD process keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1200°C-1300°C, an ammonia gas with a flow rate of 1000sccm-1200sccm, a gallium source with a flow rate of 50sccm-80sccm and an aluminum flow rate of 150sccm-240sccm. The source grows 10 periods of _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum wells on the n-type GaN layer.

Optionally, step 5 includes:

The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1100°C-1200°C, a flow rate of 2000sccm-3000sccm of ammonia gas, a flow rate of 35sccm-75sccm of gallium source and a flow rate of 150sccm-250sccm of aluminum The source is on the Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well, and the electron blocking layer of Al _y Ga _1-y N with a thickness of 50nm is grown for 10 periods;

Optionally, growing the p-type Al _z Ga _1-z N layer includes:

The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1000°C-1200°C, a flow rate of 1000sccm-2000sccm of ammonia gas, a flow rate of 45sccm-60sccm of gallium source, and a flow rate of 150sccm-250sccm of aluminum source, a magnesium source with a flow rate of 300sccm-400sccm, a silicon source with a flow rate of 200sccm-300sccm, and a boron source with a flow rate of 30sccm-70sccm, on the _{AlyGa 1-y} N electron blocking layer, a p Type Al _z Ga _1-z N layer.

Optionally, step 8 includes:

Using the MOCVD process, the reaction chamber is kept at a pressure of 20Torr-60Torr, a temperature of 1100°C-1200°C, a silicon source with a flow rate of 200sccm and a boron source with a flow rate of 30sccm. In the groove, the growth length is 50nm , a p-type Si nanowire with a diameter of 5 nm, forming a high-concentration p-type layer.

The invention discloses a light-emitting diode based on a high-concentration p-type layer of Si nanowires and a preparation method thereof. The light-emitting diode comprises from bottom to top: a c-plane sapphire substrate 1, a high-temperature AlN nucleation layer 2, and unintentionally doped GaN Layer 3, n-type GaN layer 4, Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5, Al _y Ga _1-y N electron blocking layer 6, high-concentration p-type layer 7, p-type Al _z Ga _1-z N layer 8 and p-type electrode 9, one side of the upper part of n-type GaN layer 4 is provided with n-type electrode 10, high-concentration p-type layer 7 includes p-type Si nanowire structure, p-type Si nanowire The structure includes a plurality of uniformly arranged p-type Si nanowires. Therefore, the present invention can increase the hole concentration in the p-type layer, thereby improving the hole injection efficiency, improving the luminous efficiency of the device, and at the same time alleviating the droop effect, solving the p-type layer hole injection efficiency of traditional ultraviolet and deep ultraviolet LEDs low and mitigate the droop effect.

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a structural diagram of a light-emitting diode based on a Si nanowire high-concentration p-type layer provided by the present invention;

Fig. 2 is a flow chart of a method for preparing a light-emitting diode based on a high-concentration p-type layer of Si nanowires provided by the present invention;

FIG. 3 is a schematic diagram of the process of manufacturing the light-emitting diode shown in FIG. 1 according to the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto.

Embodiment one

As shown in Figure 1, a light-emitting diode based on a high-concentration p-type layer of Si nanowires provided by the present invention includes from bottom to top: c-plane sapphire substrate 1, high-temperature AlN nucleation layer 2, unintentionally doped GaN Layer 3, n-type GaN layer 4, Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5, Al _y Ga _1-y N electron blocking layer 6, high-concentration p-type layer 7, p-type Al _z Ga _1-z N layer 8 and p-type electrode 9, one side of the upper part of n-type GaN layer 4 is provided with n-type electrode 10, n-type electrode 10 and Al _w Ga _1-w N/Al _x Ga _1-x The N multi-quantum wells 5 are not adjacently arranged, and the high-concentration p-type layer 7 contains a p-type Si nanowire structure, and the p-type Si nanowire structure includes a plurality of uniformly arranged p-type Si nanowires.

In the light-emitting diode of the present invention, the p-type Si nanowire structure utilizes the ultra-high hole concentration of Si to increase the hole concentration of the p-type layer so as to improve the hole injection efficiency and improve the luminous efficiency of the device.

The invention discloses a light-emitting diode based on a high-concentration p-type layer of Si nanowire. Type GaN layer 4, Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5, A _y Ga _1-y N electron blocking layer 6, high-concentration p-type layer 7, p-type Al _z Ga _{1 -z} N layer 8 and p-type electrode 9, one side of the upper part of n-type GaN layer 4 is provided with n-type electrode 10, high-concentration p-type layer 7 contains p-type Si nanowire structure, and p-type Si nanowire structure includes multiple Evenly arranging the p-type Si nanowires can increase the hole concentration in the p-type layer, thereby improving the hole injection efficiency and the luminous efficiency of the device, while alleviating the droop effect.

As an optional embodiment of the present invention, the high-concentration p-type layer 7 is composed of a p-type Al _z Ga _1-z N layer and a p-type Si nanowire structure whose grooves are uniformly etched out, and the p-type Si nanowire structure The wire structure includes p-type Si nanowires formed by growing p-type Si in each groove, the thickness of the high-concentration p-type layer is 100-200nm, the length of p-type Si nanowires is 50-100nm, and the diameter is 5-10nm , the adjustment range of the z content in the p-type Al _z Ga _1-z N layer is 0.1-0.5.

As an optional embodiment of the present invention, the thickness of the high-temperature AlN nucleation layer 2 is 25-45 nm; the thickness of the unintentionally doped GaN layer 3 is 1000-3000 nm; the thickness of the n-type GaN layer 4 is 1000-3000 nm; The thickness of the Al _y Ga _1-y N electron blocking layer 6 is 50nm, and the adjustment range of y is 0.25-0.65; the thickness of the p-type Al _z Ga _1-z N layer 8 is 100nm-200nm, and the adjustment range of z content is 0.1-0.5.

As an optional embodiment of the present invention, the Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5 includes multiple periodic single-layer Al _w Ga _1-w N well layers and Al _x Ga _{1 -x} N barrier layer, the thickness of the single-layer Al _w Ga _1-w N well layer and Al _x Ga _1-x N barrier layer of each period are 10-30nm and 40-60nm respectively, the adjustment of Al content w and x The ranges are 0.1-0.5 and 0.2-0.6, respectively.

As shown in Figure 2, a kind of preparation method of the light-emitting diode based on Si nanowire high-concentration p-type layer provided by the present invention comprises:

Step 1: obtaining a substrate for preparing a light-emitting diode;

Step 2: heating and high-temperature nitriding treatment on the substrate to obtain the substrate after high-temperature nitriding;

Among them, in the MOCVD process adopted by the present invention, the substrate is put into the reaction chamber; the vacuum degree of the reaction chamber is reduced to 2×10 ^-2 Torr, and hydrogen gas is introduced into the reaction chamber until the temperature of the reaction chamber reaches 400 Torr. Heat treatment at the bottom to 1000°C; keep the temperature of the reaction chamber at 1000°C, and pass ammonia gas with a flow rate of 3500 sccm into the reaction chamber after the heat treatment to carry out high-temperature nitriding of the substrate.

Step 3: Using the MOCVD process, put the substrate into the MOCVD reaction chamber, and sequentially generate a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer from bottom to top;

Step 4: growing 10 periods of Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum wells on the n-type GaN layer;

Among them, the thickness of the single-layer Al _w Ga _1-w N well layer of each period is 10-30nm, the thickness of the Al _x Ga _1-x N barrier layer is 40-60nm respectively, and the adjustment range of the Al content w is 0.1-0.5, The adjustment range of Al content x is 0.2-0.6 respectively;

Step 5: growing an Al _y Ga _{1-y N electron blocking layer with a thickness of 50 nm on the Al w Ga 1-w N /} Al x Ga 1 _{- x} N multiple quantum well;

Among them, the adjustment range of y is 0.25-0.65;

Step 6: growing a p-type Al _z Ga 1 _-z N layer on the A _y Ga _1-y N electron blocking layer;

Among them, the adjustment range of z is 0.1-0.5;

Step 7: Etching away part of the p-type Al _z Ga _1-z N layer on the p-type Al _z Ga _1-z N layer to form a plurality of uniformly arranged grooves with a length of 50-100 nm and a diameter of 5-10 nm;

Step 8: growing p-type Si in the groove to form p-type Si nanowires to obtain a high-concentration p-type layer;

Step 9: growing a p-type _{AlzGa1 -} zN layer on the high-concentration p-type layer;

Step 10: On the n-type GaN layer, deposit an n-type electrode at a position spaced from the Al _w Ga _1-w N/Al _x Ga _1-x N multiquantum well, and deposit on the p-type Al _z Ga _1-z N The p-type electrode completes the fabrication of the light-emitting diode.

The invention discloses a method for preparing a light-emitting diode based on a high-concentration p-type layer of Si nanowires. The prepared light-emitting diode includes from bottom to top: a c-plane sapphire substrate 1, a high-temperature AlN nucleation layer 2, an unintentionally doped Doped GaN layer 3, n-type GaN layer 4, Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well 5, Al _y Ga _1-y N electron blocking layer 6, high-concentration p-type layer 7, p-type Al _z Ga _1-z N layer 8 and p-type electrode 9, one side of the upper part of n-type GaN layer 4 is provided with n-type electrode 10, high-concentration p-type layer 7 includes p-type Si nanowire structure, p-type Si The nanowire structure includes a plurality of p-type Si nanowires evenly arranged, which can increase the hole concentration in the p-type layer, thereby improving the hole injection efficiency, improving the luminous efficiency of the device, and at the same time alleviating the droop effect.

As an optional implementation of the present invention, step 3 includes:

The adopted MOCVD process keeps the reaction chamber at a pressure of 20 Torr-60 Torr, a temperature of 950°C-1150°C, an ammonia gas with a flow rate of 3000sccm-4000sccm and an aluminum source with a flow rate of 30sccm-50sccm. A high-temperature AlN nucleation layer with a thickness of 25-45nm is grown on the bottom;

The pressure of the reaction chamber is kept at 30 Torr-60 Torr, the temperature is 950°C-1150°C, the ammonia gas with the flow rate of 2500sccm-3500sccm and the gallium source with the flow rate of 150sccm-170sccm are fed to grow the high-temperature AlN nucleation layer with a thickness of 1000- 3000nm unintentionally doped GaN layer;

The reaction chamber is maintained at a pressure of 20 Torr-50 Torr, a temperature of 1200°C-1300°C, ammonia gas with a flow rate of 2000sccm-3500sccm, a gallium source with a flow rate of 150sccm-250sccm, and a silicon source with a flow rate of 30sccm-50sccm. n-type GaN with a thickness of 1000-3000 nm is grown on the doped GaN layer.

As an optional implementation of the present invention, step 4 includes:

The adopted MOCVD process keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1200°C-1300°C, an ammonia gas with a flow rate of 1000sccm-1200sccm, a gallium source with a flow rate of 50sccm-80sccm and an aluminum flow rate of 150sccm-240sccm. The source grows 10 periods of _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum wells on the n-type GaN layer.

As an optional implementation of the present invention, step 5 includes:

The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1100°C-1200°C, a flow rate of 2000sccm-3000sccm of ammonia gas, a flow rate of 35sccm-75sccm of gallium source and a flow rate of 150sccm-250sccm of aluminum The source is on the Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well, and the electron blocking layer of Al _y Ga _1-y N with a thickness of 50nm is grown for 10 periods;

As an optional embodiment of the present invention, growing a p-type _{AlzGa1 -zN} layer includes:

The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1000°C-1200°C, a flow rate of 1000sccm-2000sccm of ammonia gas, a flow rate of 45sccm-60sccm of gallium source, and a flow rate of 150sccm-250sccm of aluminum source, a magnesium source with a flow rate of 300sccm-400sccm, a silicon source with a flow rate of 200sccm-300sccm, and a boron source with a flow rate of 30sccm-70sccm, on the _{AlyGa 1-y} N electron blocking layer, a p Type Al _z Ga _1-z N layer.

As an optional implementation manner of the present invention, step 8 includes:

Using the MOCVD process, the reaction chamber is kept at a pressure of 20Torr-60Torr, a temperature of 1100°C-1200°C, a silicon source with a flow rate of 200sccm and a boron source with a flow rate of 30sccm. In the groove, the growth length is 50nm , a p-type Si nanowire with a diameter of 5 nm, forming a high-concentration p-type layer.

The preparation process of the present invention will be described below by preparing a light emitting diode with a light emitting wavelength of 320nm, a light emitting diode with a light emitting wavelength of 270nm and a light emitting diode with a light emitting wavelength of 240nm.

Process 1: Prepare a light-emitting diode with a light-emitting wavelength of 320 nm.

Step a, heating and high-temperature nitriding of the substrate.

After cleaning the c-plane sapphire substrate, place it in the metal organic chemical vapor deposition MOCVD reaction chamber, reduce the vacuum degree of the reaction chamber to 2×10 ^-2 Torr; Under the condition of 400 Torr, heat the substrate to a temperature of 1000°C and keep it for 8 minutes to complete the heat treatment of the substrate substrate; place the heat-treated substrate in a reaction chamber with a temperature of 1080°C, and the flow rate is 3500 sccm ammonia gas for 4 minutes to carry out nitriding to complete the nitriding.

In step b, the MOCVD process is adopted, and the substrate is placed in the MOCVD reaction chamber, and a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer are sequentially formed from bottom to top.

As shown in Figure 3, the MOCVD process is adopted on the substrate after nitriding, the temperature of the reaction chamber is set to 950°C, and the ammonia gas with a flow rate of 3000 sccm and the aluminum source with a flow rate of 30 sccm are introduced at the same time, under the condition of maintaining a pressure of 20 Torr A high-temperature AlN nucleation layer with a thickness of 25nm is grown below, refer to sub-figure a in Fig. 3 . The MOCVD process is adopted on the AlN nucleation layer, the temperature of the reaction chamber is set to 950°C, and the ammonia gas with a flow rate of 2500 sccm and the gallium source with a flow rate of 150 sccm are introduced at the same time, and the growth thickness is maintained at a pressure of 30 Torr. 1000 nm layer of unintentionally doped GaN, in Fig. 3 refer to sub-figure b. The MOCVD process is adopted on the unintentionally doped GaN layer, the temperature of the reaction chamber is set to 1200°C, and the three gases of ammonia gas with a flow rate of 2000 sccm, a gallium source with a flow rate of 150 sccm and a silicon source with a flow rate of 30 sccm are introduced at the same time. An n-type GaN layer with a thickness of 1000 nm is grown under the condition of a pressure of 20 Torr, refer to sub-figure c in FIG. 3 .

Step c, growing Al _0.1 Ga _0.9 N/Al _0.2 Ga _0.8 N multiple quantum wells.

Referring to sub-figure d in Figure 3, under the conditions of the temperature of the reaction chamber at 1000°C and the pressure of 40 Torr, ammonia gas with a flow rate of 1000 sccm is introduced at the same time; the flow rate of the gallium source is kept at 60 sccm, and the flow rate of the aluminum source is 150 sccm. Grow a 10nm Al _0.1 Ga _0.9 N layer on top of the GaN layer by MOCVD; keep the gallium source flow at 50 sccm and the aluminum source flow at 170 sccm, grow a 40nm Al _0.2 Ga _0.8 N layer on the Al _0.1 Ga _0.9 N layer; repeat the generation Al _0.1 Ga _0.9 N layer and Al _0.2 Ga _0.8 N layer, Al _0.1 Ga _0.9 N/Al _0.2 Ga _0.8 N multiple quantum wells were grown for 10 cycles.

Step d, growing an Al _0.25 Ga _0.75 N electron blocking layer.

Referring to sub-picture e in Figure 3, MOCVD process is adopted on the Al _0.1 Ga _0.9 N/Al _0.2 Ga _0.8 N multiple quantum wells, the temperature of the reaction chamber is set to 1100°C, and the flow rate of ammonia gas is 2000 sccm, and the flow rate is 35 sccm The gallium source and the aluminum source with a flow rate of 150 sccm are used to grow an Al _0.25 Ga _0.75 N electron blocking layer with a thickness of 50 nm under the condition of maintaining a pressure of 40 Torr.

Step e, growing a high-concentration p-type layer.

The MOCVD process was adopted on the Al _0.25 Ga _0.75 N electron blocking layer, the temperature of the reaction chamber was set at 1100°C, and the ammonia gas with a flow rate of 1000 sccm, the gallium source with a flow rate of 60 sccm, the aluminum source with a flow rate of 150 sccm, and the Magnesium source these four gases, _grow a p-type Al _0.1 Ga _0.9 N _layer with a thickness of 100nm under the condition of maintaining a pressure of 40Torr, refer to sub-figure f in Figure 3; Part of the p-type Al _0.1 Ga _0.9 N layer is etched away on the layer to form a pattern with a length of 50nm and a diameter of 5nm for growing p-type Si nanowires, refer to subgraph g in Figure 3; after etching, the p The MOCVD process is adopted on the Al _0.1 Ga _0.9 N layer, the temperature of the reaction chamber is set to 1000°C, and the silicon source with a flow rate of 200 sccm and the boron source with a flow rate of 30 sccm are introduced at the same time, under the condition of maintaining a pressure of 40 Torr Next grow p-type Si nanowires with a length of 50 nm and a diameter of 5 nm, refer to sub-figure h in Fig. 3 .

Step f, growing a p-type Al _0.1 Ga _0.9 N layer.

On the high-concentration p-type layer, the MOCVD process is adopted, the temperature of the reaction chamber is set to 1100°C, and the ammonia gas with a flow rate of 1000 sccm, the gallium source with a flow rate of 60 sccm, the aluminum source with a flow rate of 150 sccm, and the magnesium source with a flow rate of 300 sccm are introduced. Four kinds of gases were used to grow a p-type Al _0.1 Ga _0.9 N layer with a thickness of 100nm under the condition of maintaining a pressure of 40 Torr. After the growth was completed, the temperature of the MOCVD reaction chamber was maintained at 1000°C, and then annealed for 9 minutes in an H ₂ atmosphere, as shown in Fig. Refer to subgraph i in 3.

Step g, depositing electrodes.

Maintain the temperature of the reaction chamber at 1000°C, anneal for 9 minutes in H ₂ atmosphere, and then use the method of sputtering metal to deposit n-type electrodes on the n-type GaN layer and p-type electrodes on the p-type GaN layer to complete the LED Fabrication of the device, refer to subfigure j in Figure 3.

Process 2, preparing a light emitting diode with a light emitting wavelength of 270nm.

Step a, heating and high-temperature nitriding of the substrate.

After cleaning the c-plane sapphire substrate, place it in the metal organic chemical vapor deposition MOCVD reaction chamber, reduce the vacuum degree of the reaction chamber to 2×10 ^-2 Torr; Under the condition of 500 Torr, the substrate is heated to a temperature of 1050°C and kept for 6 minutes to complete the heat treatment of the substrate substrate; the heat-treated substrate is placed in a reaction chamber with a temperature of 1130°C, and the flow rate is 4000 sccm ammonia gas for 3 minutes for nitriding to complete the nitriding.

In step b, the MOCVD process is adopted, and the substrate is placed in the MOCVD reaction chamber, and a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer are sequentially formed from bottom to top.

As shown in Figure 3, the MOCVD process is used on the nitrided substrate, the temperature of the reaction chamber is set to 1050°C, and the ammonia gas with a flow rate of 3500 sccm and the aluminum source with a flow rate of 40 sccm are introduced at the same time, under the condition of maintaining a pressure of 40 Torr A high-temperature AlN nucleation layer with a thickness of 35 nm is grown under the reference sub-figure a in Fig. 3 . The MOCVD process was adopted on the AlN nucleation layer, the temperature of the reaction chamber was set to 1000°C, and the ammonia gas with a flow rate of 3000 sccm and the gallium source with a flow rate of 160 sccm were introduced at the same time, and the growth thickness was maintained at a pressure of 40 Torr. 2000 nm layer of unintentionally doped GaN, in Fig. 3 refer to sub-figure b. The MOCVD process is adopted on the unintentionally doped GaN layer, the temperature of the reaction chamber is set at 1250°C, and the three gases of ammonia gas with a flow rate of 3000 sccm, a gallium source with a flow rate of 200 sccm and a silicon source with a flow rate of 40 sccm are introduced at the same time. An n-type GaN layer with a thickness of 2000 nm is grown under the condition of a pressure of 40 Torr, refer to sub-figure c in FIG. 3 .

Step c, growing Al _0.4 Ga _0.6 N/Al _0.5 Ga _0.5 N multiple quantum wells.

Referring to sub-figure d in Figure 3, under the conditions of the temperature of the reaction chamber at 1100°C and the pressure of 50 Torr, ammonia gas with a flow rate of 1100 sccm is introduced simultaneously; the flow rate of the gallium source is kept at 70 sccm, and the flow rate of the aluminum source is 200 sccm. Grow a 20nm Al _0.4 Ga _0.6 N layer on top of the GaN layer by MOCVD process; keep the gallium source flow at 60 sccm and the aluminum source flow at 220 sccm, grow a 50nm Al _0.5 Ga _0.5 N layer on the Al _0.4 Ga _0.6 N layer; repeat the generation Al _0.4 Ga _0.6 N layer and Al _0.5 Ga _0.5 N process, a total of 10 cycles of Al _0.4 Ga _0.6 N/Al _0.5 Ga _0.5 N multiple quantum wells were grown.

Step d, growing an Al _0.55 Ga _0.45 N electron blocking layer.

Referring to sub-figure e in Figure 3, MOCVD process is adopted on the Al _0.4 Ga _0.6 N/Al _0.5 Ga _0.3 N multiple quantum wells, the temperature of the reaction chamber is set to 1150°C, and the flow rate of ammonia gas is 2500 sccm, and the flow rate is 55 sccm The gallium source and the aluminum source with a flow rate of 200 sccm are used to grow an Al _0.55 Ga _0.45 N electron blocking layer with a thickness of 50 nm under the condition of maintaining a pressure of 50 Torr.

Step e, growing a high-concentration p-type layer.

The MOCVD process is adopted on the Al _0.55 Ga _0.45 N electron blocking layer, the temperature of the reaction chamber is set to 1150°C, and the ammonia gas with a flow rate of 1500 sccm, the gallium source with a flow rate of 55 sccm, the aluminum source with a flow rate of 200 sccm, and the aluminum source with a flow rate of 350 sccm are introduced. Magnesium source these four gases, grow _a p-type Al _0.4 Ga _0.6 N layer with a thickness of 150nm under the condition of maintaining a pressure of 50Torr, refer to sub-figure f in _Figure 3; Part of the p-type Al _0.4 Ga _0.6 N layer is etched away on the layer to form a pattern with a length of 75nm and a diameter of 7nm for growing p-type Si nanowires, refer to subgraph g in Figure 3; after etching, the p The MOCVD process is adopted on the Al _0.4 Ga _0.6 N layer, the temperature of the reaction chamber is set at 1100°C, and the silicon source with a flow rate of 250 sccm and the boron source with a flow rate of 50 sccm are introduced at the same time, under the condition of maintaining a pressure of 50 Torr grow a p-type p-type Si nanowire with a length of 75nm and a diameter of 7nm, refer to sub-figure h in Figure 3;

Step f, growing a p-type Al _0.4 Ga _0.6 N layer.

The MOCVD process is adopted on the high-concentration p-type layer, the temperature of the reaction chamber is set to 1150°C, and the ammonia gas with a flow rate of 1500 sccm, the gallium source with a flow rate of 55 sccm, the aluminum source with a flow rate of 200 sccm, and the magnesium source with a flow rate of 350 sccm are introduced. Four gases were used to grow a p-type Al _0.4 Ga _0.6 N layer with a thickness of 150 nm under the condition of maintaining a pressure of 50 Torr. After the growth was completed, the temperature of the MOCVD reaction chamber was maintained at 1050 ° C, and then annealed for 7 minutes under H ₂ atmosphere, as shown in Fig. Refer to subgraph i in 3.

Step g, depositing electrodes.

Maintain the temperature of the reaction chamber at 1200°C, anneal for 5 minutes in the _H2 atmosphere, and then use the method of sputtering metal to deposit n-type electrodes on the n-type GaN layer and p-type electrodes on the p-type GaN layer to complete the LED Fabrication of the device, refer to subfigure j in Figure 3.

Example 3, preparing a light emitting diode with a light emitting wavelength of 240nm.

Step a, heating and high-temperature nitriding of the substrate.

After cleaning the c-plane sapphire substrate, place it in the metal organic chemical vapor deposition MOCVD reaction chamber, reduce the vacuum degree of the reaction chamber to 2×10 ^-2 Torr; Under the condition of 550 Torr, the substrate is heated to a temperature of 1100°C and kept for 4 minutes to complete the heat treatment of the substrate substrate; the heat-treated substrate is placed in a reaction chamber with a temperature of 1180°C, and the flow rate is 4500 sccm ammonia gas for 2 minutes to carry out nitriding to complete the nitriding.

In step b, the MOCVD process is adopted, and the substrate is placed in the MOCVD reaction chamber, and a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer are sequentially formed from bottom to top.

As shown in Figure 3, the MOCVD process is used on the nitrided substrate, the temperature of the reaction chamber is set to 1150 ° C, and the ammonia gas with a flow rate of 4000 sccm and the aluminum source with a flow rate of 50 sccm are introduced at the same time, and the pressure is maintained at 60 Torr. A high-temperature AlN nucleation layer with a thickness of 45 nm is grown below, refer to sub-figure a in Fig. 3 . The MOCVD process is adopted on the AlN nucleation layer, the temperature of the reaction chamber is set to 1150°C, and the ammonia gas with a flow rate of 3500 sccm and the gallium source gas with a flow rate of 170 sccm are introduced at the same time, and the growth thickness is 3000 nm under the condition of maintaining a pressure of 60 Torr. The unintentionally doped GaN layer, in Fig. 3 refer to sub-figure b. The MOCVD process is adopted on the unintentionally doped GaN layer, the temperature of the reaction chamber is set to 1300°C, and the three gases of ammonia gas with a flow rate of 3500 sccm, a gallium source with a flow rate of 250 sccm and a silicon source with a flow rate of 50 sccm are introduced at the same time. An n-type GaN layer with a thickness of 3000 nm is grown under the condition of a pressure of 50 Torr, refer to sub-figure c in FIG. 3 .

Step c, growing Al _0.5 Ga _0.5 N/Al _0.6 Ga _0.4 N multiple quantum wells.

Referring to sub-figure d in Figure 3, under the conditions of the temperature of the reaction chamber at 1200°C and the pressure of 60 Torr, ammonia gas with a flow rate of 1200 sccm is introduced at the same time; the flow rate of the gallium source is kept at 80 sccm, and the flow rate of the aluminum source is 220 sccm. Grow a 30nm Al _0.5 Ga _0.5 N layer on top of the GaN layer by MOCVD; keep the gallium source flow at 70 sccm and the aluminum source flow at 240 sccm, grow a 60nm Al _0.6 Ga _0.4 N layer on the Al _0.5 Ga _0.5 N layer; repeat the generation Al _0.5 Ga _0.5 N and Al _0.6 Ga _0.4 N layers are grown together for 10 cycles of Al _0.5 Ga _0.5 N/Al _0.6 Ga _0.4 N multiple quantum wells.

Step d, growing an Al _0.65 Ga _0.35 N electron blocking layer.

Referring to sub-picture e in Figure 3, MOCVD process is adopted on the Al _0.5 Ga _0.5 N/Al _0.6 Ga _0.4 N multiple quantum wells, the temperature of the reaction chamber is set to 1200°C, and the flow rate of ammonia gas is 3000 sccm and the flow rate is 75 sccm. The gallium source and the aluminum source with a flow rate of 250 sccm are used to grow an Al _0.55 Ga _0.45 N electron blocking layer with a thickness of 50 nm under the condition of maintaining a pressure of 60 Torr.

Step e, growing a high-concentration p-type layer.

The MOCVD process is adopted on the Al _0.65 Ga _0.35 N electron blocking layer, the temperature of the reaction chamber is set to 1200°C, and the ammonia gas with a flow rate of 2000 sccm, the gallium source with a flow rate of 45 sccm, the aluminum source with a flow rate of 250 sccm, and the aluminum source with a flow rate of 400 sccm are introduced. Magnesium source these four gases, grow a p-type Al _0.5 Ga _0.5 N _layer with a thickness of 200nm under the condition of maintaining a pressure of 60Torr, _refer to sub-figure f in Figure 3; Part of the p-type Al _0.5 Ga _0.5 N layer is etched away on the layer to form a pattern with a length of 100nm and a diameter of 10nm for growing p-type Si nanowires, refer to subgraph g in Figure 3; after etching, the p The MOCVD process is adopted on the type Al _0.5 Ga _0.5 N layer, the temperature of the reaction chamber is set at 1200°C, and the silicon source with a flow rate of 300 sccm and the boron source with a flow rate of 70 sccm are introduced at the same time, under the condition of maintaining a pressure of 60 Torr grow a p-type Si nanowire with a length of 100nm and a diameter of 10nm, refer to sub-figure h in Figure 3;

Step f, growing a p-type Al _0.5 Ga _0.5 N layer.

The MOCVD process is adopted on the high-concentration p-type layer, the temperature of the reaction chamber is set to 1200°C, and the ammonia gas with a flow rate of 2000 sccm, the gallium source with a flow rate of 45 sccm, the aluminum source with a flow rate of 250 sccm, and the magnesium source with a flow rate of 400 sccm are introduced. Four kinds of gases were used to grow a p-type Al _0.5 Ga _0.5 N layer with a thickness of 200nm under the condition of maintaining a pressure of 60 Torr. After the growth was completed, the temperature of the MOCVD reaction chamber was maintained at 1100°C, and then annealed in an H ₂ atmosphere for 5 minutes, as shown in Fig. Refer to subgraph i in 3.

Step g, depositing electrodes.

Maintain the temperature of the reaction chamber at 1400°C, anneal for 3 minutes in H ₂ atmosphere, and then use the method of sputtering metal to deposit n-type electrodes on the n-type GaN layer and p-type electrodes on the p-type GaN layer to complete the LED Fabrication of the device, refer to subfigure j in Figure 3.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (9)

1. A light-emitting diode based on a high-concentration p-type layer of Si nanowires, characterized in that, the light-emitting diode comprises from bottom to top: a c-plane sapphire substrate (1), a high-temperature AlN nucleation layer (2), non- Intentionally doped GaN layer (3), n-type GaN layer (4), Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum wells (5), A _y Ga _1-y N electron blocking layer ( 6), high-concentration p-type layer (7), p-type Al _z Ga _1-z N layer (8) and p-type electrode (9), one side of n-type GaN layer (4) top is provided with n-type electrode ( 10), the n-type electrode (10) is not adjacent to the _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum well (5), and the high-concentration p-type layer (7) Containing a p-type Si nanowire structure, the p-type Si nanowire structure includes a plurality of uniformly arranged p-type Si nanowires; The high-concentration p-type layer (7) is composed of a p-type Al _z Ga _1-z N layer uniformly provided with a plurality of grooves and a p-type Si nanowire structure, and the p-type Si nanowire structure is included in each The p-type Si nanowire formed by growing p-type Si in each groove, the thickness of the high-concentration p-type layer is 100-200nm, the length of the p-type Si nanowire is 50-100nm, and the diameter is 5-10nm, p-type The adjustment range of the z content in the Al _z Ga _1-z N layer is 0.1-0.5. 2. The light emitting diode according to claim 1, characterized in that, the thickness of the high temperature AlN nucleation layer (2) is 25-45nm; the thickness of the unintentionally doped GaN layer (3) is 1000-3000nm The thickness of the n-type GaN layer (4) is 1000-3000nm; the thickness of the _{AlyGa 1-y} N electron blocking layer (6) is 50nm, and the adjustment range of y is 0.25-0.65; the p The thickness of the type Al _z Ga _1-z N layer (8) is 100nm-200nm, and the adjustment range of z content is 0.1-0.5. 3. The light emitting diode according to claim 1, characterized in that, the Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well (5) comprises a plurality of periodic single-layer Al _w Ga _{1- w} N well layer and Al _x Ga _1-x N barrier layer, the thickness of each period of single-layer Al _w Ga _1-w N well layer and Al _x Ga _1-x N barrier layer is 10-30nm and 40- 60nm, the adjustment ranges of Al content w and x are 0.1-0.5 and 0.2-0.6 respectively. 4. A method for preparing a light-emitting diode based on a high-concentration p-type layer of Si nanowires, comprising: Step 1: obtaining a substrate for preparing a light-emitting diode; Step 2: heating and high-temperature nitriding treatment on the substrate to obtain the substrate after high-temperature nitriding; Step 3: Using the MOCVD process, the substrate is placed in the MOCVD reaction chamber, and a high-temperature AlN nucleation layer, an unintentionally doped GaN layer, and an n-type GaN layer are sequentially generated from bottom to top; Step 4: growing 10 periods of Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum wells on the n-type GaN layer; Among them, the thickness of the single-layer Al _w Ga _1-w N well layer of each period is 10-30nm, the thickness of the Al _x Ga _1-x N barrier layer is 40-60nm respectively, and the adjustment range of the Al content w is 0.1-0.5, The adjustment range of Al content x is 0.2-0.6 respectively; Step 5: growing an Al _y Ga _{1-y N electron blocking layer with a thickness of 50 nm on the Al w Ga 1-w N /} Al x Ga 1 _{- x} N multiple quantum well; Among them, the adjustment range of y is 0.25-0.65; Step 6: growing a p-type Al _z Ga 1 _-z N layer on the A _y Ga _1-y N electron blocking layer; Among them, the adjustment range of z is 0.1-0.5; Step 7: Etching away part of the p-type Al _z Ga _1-z N layer on the p-type Al _z Ga _1-z N layer to form a plurality of uniformly arranged concave holes with a length of 50-100 nm and a diameter of 5-10 nm groove; Step 8: growing p-type Si in the groove to form p-type Si nanowires to obtain a high-concentration p-type layer; Step 9: growing a p-type _{AlzGa1 -zN} layer on the high-concentration p-type layer; Step 10: On the n-type GaN layer, deposit an n-type electrode at a position spaced from the Al _w Ga _1-w N/Al _x Ga _1-x N multiquantum well, and deposit an n-type electrode on the p-type Al _z Ga _1-z N A p-type electrode is deposited on it to complete the fabrication of the light emitting diode. 5. preparation method according to claim 4, is characterized in that, described step 3 comprises: The adopted MOCVD process keeps the reaction chamber at a pressure of 20 Torr-60 Torr, a temperature of 950°C-1150°C, an ammonia gas with a flow rate of 3000sccm-4000sccm and an aluminum source with a flow rate of 30sccm-50sccm. A high-temperature AlN nucleation layer with a thickness of 25-45nm is grown on the bottom; The pressure of the reaction chamber is kept at 30 Torr-60 Torr, the temperature is 950°C-1150°C, the ammonia gas with the flow rate of 2500sccm-3500sccm and the gallium source with the flow rate of 150sccm-170sccm are fed to grow the high-temperature AlN nucleation layer with a thickness of 1000- 3000nm unintentionally doped GaN layer; The reaction chamber is maintained at a pressure of 20 Torr-50 Torr, a temperature of 1200°C-1300°C, ammonia gas with a flow rate of 2000sccm-3500sccm, a gallium source with a flow rate of 150sccm-250sccm, and a silicon source with a flow rate of 30sccm-50sccm. n-type GaN with a thickness of 1000-3000 nm is grown on the doped GaN layer. 6. preparation method according to claim 4, is characterized in that, described step 4 comprises: The adopted MOCVD process keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1200°C-1300°C, an ammonia gas with a flow rate of 1000sccm-1200sccm, a gallium source with a flow rate of 50sccm-80sccm and an aluminum flow rate of 150sccm-240sccm. The source grows 10 periods of _{AlwGa1 -wN} / _{AlxGa1 -xN} multiple quantum wells on the n-type GaN layer. 7. preparation method according to claim 4, is characterized in that, described step 5 comprises: The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1100°C-1200°C, a flow rate of 2000sccm-3000sccm of ammonia gas, a flow rate of 35sccm-75sccm of gallium source and a flow rate of 150sccm-250sccm of aluminum The source is on the Al _w Ga _1-w N/Al _x Ga _1-x N multiple quantum well, and an electron blocking layer of Al _y Ga _1-y N with a thickness of 50 nm is grown for 10 periods. 8. The preparation method according to claim 4, wherein said growing p-type _{AlzGa1 -zN} layer comprises: The MOCVD process adopted keeps the reaction chamber at a pressure of 40Torr-60Torr, a temperature of 1000°C-1200°C, a flow rate of 1000sccm-2000sccm of ammonia gas, a flow rate of 45sccm-60sccm of gallium source, and a flow rate of 150sccm-250sccm of aluminum source, a magnesium source with a flow rate of 300sccm-400sccm, a silicon source with a flow rate of 200sccm-300sccm, and a boron source with a flow rate of 30sccm-70sccm, on the _{AlyGa 1-y} N electron blocking layer, a p Type Al _z Ga _1-z N layer. 9. preparation method according to claim 4, is characterized in that, described step 8 comprises: The MOCVD process adopted keeps the reaction chamber at a pressure of 20Torr-60Torr, a temperature of 1100°C-1200°C, and a silicon source with a flow rate of 200 sccm and a boron source with a flow rate of 30 sccm. In the groove, the growth length p-type Si nanowires with a diameter of 50nm and a diameter of 5nm form a high-concentration p-type layer.