CN205752223U - A kind of LED flip chip - Google Patents

Abstract

A kind of LED flip chip, this LED flip chip includes: substrate, the epitaxial layer being formed on described substrate, the reflecting layer that is formed on described epitaxial layer, be formed with Graphene barrier layer on described reflecting layer, N lead-in wire electrode be formed at run through described Graphene barrier layer, reflecting layer, p-type gallium nitride layer, luminescent layer until n type gallium nitride layer surface N electrode hole in；Gap between the exposed surface of described epitaxial layer, the exposed surface on Graphene barrier layer, the exposed upper of substrate and N electrode hole and N lead-in wire electrode is formed with insulating barrier, N pad and the P pad of mutually insulated it is formed with on described insulating barrier, described N pad is formed with N lead-in wire electrode and is conductively connected, and described P pad is formed with Graphene barrier layer and is conductively connected.This utility model can not only stop the metal material in reflecting layer to migrate by Graphene barrier layer effectively, and can promote luminous efficiency and the brightness of chip.

Description

A kind of LED flip chip

Technical field

This utility model belongs to semiconductor optoelectronic chip technology field, particularly relates to a kind of LED flip chip structure.

Background technology

Generally use metal-organic ligand (MOCVD), molecular beam epitaxy (MBE) or other epitaxy technology in indigo plant The lamination of the semiconductor layer being epitaxially grown different composition and concentration of dopant on gem, carborundum or other suitable substrate comes Manufacture group III-nitride luminescent device.This lamination usually includes the one or more n formed on substrate with such as Si doping Type layer, one or more luminescent layers in the active area being formed in one or more n-layer and formed on the active area With such as Mg doping one or more p-type layer, and in n-type area and p-type area formed electrical contact.By group III-nitride device Part is formed as being inverted or flip chip devices, wherein, is formed in the same side of semiconductor structure both N with P contact, and from Light is extracted in that side contacting relative semiconductor structure.

Silver is often as reflective p-contact, it is known that it is easily by by transporting that mechanical stress, chemical reaction or electromigration cause Impact.United States Patent (USP) 6,946,685 describe a kind of group III-nitride LED with silver-colored P contact, which teach " silver electrode gold There is dampness and electric field (field such as, such as gradually produced) owing to applying running voltage in the contact position of device in genusization In the case of stand electrochemical migration.The electrochemical migration of the silver metallized PN junction to device causes the alternating current bypass road crossing over knot Footpath, which reduces the efficiency of device.

Fig. 1 is the luminescent device including semiconductor structure, and this semiconductor structure is included in III-V nitride quasiconductor Luminescent active region 130A between the P-type layer 140 of n-layer 120 and III nitride semiconductor, in p-type layer 140, deposition includes The P electrode 160 of silver metal, and n-electrode (not shown) is closed with n-layer 120 Rhizoma Nelumbinis.Providing in this semiconductor structure can be for Cross over described electrode and apply the signal of telecommunication to cause the photoemissive means from active area, and provide for preventing silver metal From p-electrode 160 towards the migration obstacle 175 of the electrochemical migration of active area.This migration obstacle 175 is conductive protection sheet, Protective sheet is surrounded p-electrode 160 completely and covers the edge 12 of p-electrode 160.In order to seal silver contact, first with conductive protection sheet From table top (edge of (mesa) carries out etch-back to silver, owing to migrating obstacle 175 material usually containing Ti or W, but Ti/W visible light absorbing material, it is different from silver P electrode 160 and has reflexive, therefore at the edge of reflexive P electrode 160 One " black vaginal discharge " 10 (i.e. migrating the part exposed after obstacle covers Ag electrode), black vaginal discharge 10 can be formed between 12 and the edge of table top Visible ray can be absorbed, thus reduce the light efficiency of LED.

Utility model content

The purpose of this utility model is to provide a kind of efficiency that can promote LED and the LED flip chip of brightness.

To achieve these goals, this utility model takes following technical solution:

A kind of LED flip chip, including: substrate, the epitaxial layer being formed on described substrate, it is formed on described epitaxial layer Reflecting layer, described epitaxial layer includes p-type gallium nitride layer, luminescent layer and n type gallium nitride layer, described reflecting layer is formed with graphite Alkene barrier layer, N lead-in wire electrode is formed at and runs through described Graphene barrier layer, reflecting layer, p-type gallium nitride layer, luminescent layer until N In the N electrode hole on type gallium nitride layer surface；The exposed surface of described epitaxial layer, the exposed surface on Graphene barrier layer, substrate Gap between exposed upper and N electrode hole and N lead-in wire electrode is formed with insulating barrier, described insulating barrier is formed the most absolutely The N pad of edge and P pad, described N pad is formed with N lead-in wire electrode and is conductively connected, and described P pad is formed with Graphene barrier layer It is conductively connected.

Further, the exposed surface on described Graphene barrier layer is formed with P lead-in wire electrode, and described insulating barrier is formed at institute State the exposed surface of epitaxial layer, the P lead-in wire exposed surface of electrode, the exposed upper of substrate and N electrode hole and N lead-in wire electrode it Between gap, described P pad is conductively connected by electrode and the Graphene barrier layer formation of described P lead-in wire.

Further, described Graphene barrier layer is completely covered the exposed surface in reflecting layer.

Further, described Graphene barrier layer is single or multiple lift Graphene.

Further, described N lead-in wire electrode and P lead-in wire electrode are that identical material is made and deposited simultaneously forming.

From above technical scheme, on deposited graphite alkene barrier layer, surface, reflecting layer, owing to Graphene barrier layer is not The material of extinction, it is possible to effectively stop the metal material in reflecting layer to migrate, the most effectively solution " black surround " problem, and graphite Alkene material, because of conduction, heat conduction and the compactness of its brilliance, can be used to do the barrier material of metal electrode, to promote upside-down mounting The performance of LED chip, reduces the absorption of light, promotes LED flip chip luminous efficiency and brightness.

Accompanying drawing explanation

Fig. 1 is the structural representation of a kind of light emitting semiconductor device in prior art；

Fig. 2 is the structural representation of this utility model embodiment 1；

Fig. 3 to Figure 11 is the preparation process schematic diagram of this utility model embodiment 1LED flip-chip；

Figure 12 is the schematic diagram that this utility model embodiment 2 forms lead-in wire electrode step；

Figure 13 is the schematic diagram that embodiment 2 forms insulating barrier step；

Figure 14 is the schematic diagram that embodiment 2 forms pad step.

Detailed description of the invention

Below in conjunction with the accompanying drawings this utility model is described in detail, when describing this utility model embodiment in detail, for ease of Illustrating, representing that the accompanying drawing of device architecture can be disobeyed general ratio and be done partial enlargement, and described schematic diagram is example, it is at this Should not limit the scope of this utility model protection.It should be noted that accompanying drawing use simplify form and all use non-accurately Ratio, only in order to purpose convenient, clearly aid illustration this utility model embodiment.

Embodiment 1

As in figure 2 it is shown, the LED flip chip of the present embodiment includes substrate 1, the n type gallium nitride layer 11 that is positioned on substrate 1, The luminescent layer 12, the p-type gallium nitride layer 13 being positioned on luminescent layer 12 that are positioned on n type gallium nitride layer 11, it is positioned at p-type gallium nitride layer 13 On reflecting layer 15 and the Graphene barrier layer 14 that is covered on reflecting layer 15, the Graphene barrier layer 14 of the present embodiment is complete Cover the exposed surface in reflecting layer 15.Graphene barrier layer 14, reflecting layer 15, p-type gallium nitride layer are run through in N electrode hole (non-label) 13, luminescent layer 12 is until n type gallium nitride layer 11 surface, and N lead-in wire electrode 32 is formed in N electrode hole.P lead-in wire electrode 31 is formed Exposed surface in Graphene barrier layer 14.Outside the exposed surface, P the lead-in wire exposed surface of electrode 31, substrate 1 of epitaxial layer Gap between dew upper surface and N electrode hole and N lead-in wire electrode is formed with insulating barrier 16.Insulating barrier 16 is formed the most absolutely P the pad 27 and N pad 26 of edge, P pad 27 electrically connects with P lead-in wire electrode 31, and N pad 26 electrically connects with N lead-in wire electrode 32.

Below in conjunction with Fig. 3 to Figure 11, the preparation method of the LED flip chip of the present embodiment is described in detail:

Step one, it is provided that substrate 1 grown epitaxial layer, the substrate 1 of the present embodiment is Sapphire Substrate, passes through MOCVD (Metal-organic Chemical Vapor Deposition, metallo-organic compound chemical gaseous phase deposition) is at sapphire Substrate 1 surface growing epitaxial layers, epitaxial layer growth process is followed successively by: at Sapphire Substrate 1 superficial growth n type gallium nitride layer 11, on n type gallium nitride layer 11 grow luminescent layer 12, on described luminescent layer 12 growing P-type gallium nitride layer 13 (Fig. 3)；

Step 2, forms reflecting layer 15, as shown in Figure 4 and Figure 5, uses evaporation and photoetching process at p-type gallium nitride layer 13 Covering reflecting layer, surface 15, reflecting layer 15 can be aluminum, both alloy silver-colored or aforementioned；

Step 3, forms Graphene barrier layer 14, as shown in Figure 6, migrates Graphene barrier layer 14 by chemical technology, make It covers at surface, reflecting layer 15 and surrounding sidewall thereof, and migrating graphene layer by chemical technology is prior art, few at this Endure and state；Graphene barrier layer 14 can be single or multiple lift Graphene；

Form isolated groove 3 and N electrode hole 4, use ICP etch process to form groove 3, the bottom of groove 3 at epitaxial layer Expose Sapphire Substrate 1 surface, so that epitaxial layer forms the independent chip that insulate each other；It is deposited with by employing and photoetching Technique, makes Graphene barrier layer 14, reflecting layer 15 form step 9 with p-type gallium nitride layer 13 surface；

Chip is performed etching, runs through Graphene barrier layer 14, reflecting layer 15, p-type gallium nitride to be formed at chip surface Layer 13, luminescent layer 12 until the N electrode hole 4 on n type gallium nitride layer 11 surface, the quantity in N electrode hole 4 can be multiple and Chip surface is uniformly distributed；

Step 5, forms lead-in wire electrode, as it is shown in fig. 7, form N lead-in wire electrode 32 N electrode hole 4 in, i.e. N goes between electrode 32 are electrically connected to form Ohmic contact with n type gallium nitride layer 11, and N lead-in wire electrode 32 can be cylindrical shape, for avoiding N lead-in wire electrode 32 short circuit p-type gallium nitride layers 13 and n type gallium nitride layers 11, N lead-in wire electrode 32 periphery wall and N electrode hole 4 inwall mutually insulated every Open；In the formation of Graphene barrier layer 14 exposed surface, there is the P lead-in wire electrode 31, P of wiring pattern by sputtering or evaporation process Lead-in wire electrode 31 electrically connects with Graphene barrier layer 14；

N lead-in wire the electrode 32 and P lead-in wire electrode 31 of the present embodiment uses identical material and deposits simultaneously forming, and can subtract The flow process that LED chip produces less, reduces cost, N lead-in wire electrode and P lead-in wire electrode and can use Cr or Al with highly reflective energy Or Ni or Ti or Au or Pt or the alloy of previous materials, to decrease the absorption of light；And N lead-in wire electrode and P lead-in wire electrode are also There is barrier function, preferably achieve and reflecting layer is protected；

Step 6, is formed insulating barrier, as shown in Figure 8, is drawn at exposed surface, the P of epitaxial layer by sputtering or spraying coating process Gap between the exposed surface of line electrode 31, the exposed upper of substrate 1 and N electrode hole and N lead-in wire electrode forms insulating barrier 16, insulating layer material can be aluminium nitride, silicon dioxide, silicon nitride, aluminium sesquioxide, Bragg reflecting layer DBR (TiO₂/SiO₂), Silica gel or resin or acrylic acid, thickness is 0.3um～5um；

Step 7, forms contact hole, as shown in FIG. 9 and 10, uses photoetching and etching technique to beat on insulating barrier 16 surface Hole, etches N-type contact hole 6 and p-type contact hole 5 respectively, and wherein, N-type contact hole 6 is connected with N lead-in wire electrode 32 surface, p-type Contact hole 5 is connected with P lead-in wire electrode 31 surface, and chip surface is all distributed N-type contact hole 6 and p-type contact hole 5；

Step 8, forms pad, as shown in figs. 2 and 11, manufactures phase by printing and electroplating technology on insulating barrier 16 N pad 26 and P pad 27, N pad 26 and the P pad 27 of insulation covers on insulating barrier 16 surface in part mutually, and N pad 26 passes through N-type contact hole 6 contacts with N lead-in wire electrode 32, and P pad 27 is contacted by p-type contact hole 5 and P lead-in wire electrode 31, N pad 26 is symmetrical with P pad 27.P pad and N pad thickness can be 0.5um～2um, the interval between P pad and N pad >= 150um, material is preferably aluminum or nickel or titanium or platinum or gold.

This utility model is the transparent material of not extinction at overlying lid Graphene barrier layer, reflecting layer, Graphene, it is possible to have Effect ground stops the metal material from reflecting layer to migrate, and promotes efficiency and the brightness of LED；And, grapheme material is the most Know the material (thermal conductivity exceedes diamond) that heat conduction is best, therefore do barrier layer with grapheme material, it is also possible to carry further Rise the heat dispersion of flip LED chips, the stability of boost device.Additionally, grapheme material is also to be currently known densification the most Material, the least all cannot penetrate Graphene to He atom, therefore Graphene is the most excellent barrier material, aforementioned Embodiment is used for doing the protection material of Ag electrode, the infiltration of steam can be stopped, thus avoid device to lose efficacy because silver migrates.

Embodiment 2

The present embodiment place different from embodiment 1 is: as shown in figure 12, only forms in forming lead-in wire electrode step N goes between electrode 32, not be used in Graphene barrier layer 14 exposed surface and forms P and go between electrode；The N lead-in wire structure of electrode and position with Embodiment 1 identical.As shown in figure 13, at the exposed surface of epitaxial layer, the exposed surface on Graphene barrier layer 14, substrate 1 Gap between exposed upper and N electrode hole and N lead-in wire electrode forms insulating barrier 16；As shown in figure 14, on insulating barrier 16 The logical N pad 26 forming mutually insulated and P pad 27, N pad 26 forms conduction even by N-type contact hole with N lead-in wire electrode 32 Connecing, P pad 27 is formed by p-type contact hole and Graphene barrier layer 14 and is conductively connected.The present embodiment is at Graphene barrier layer table Face does not cover P lead-in wire electrode, but directly utilizes the electric conductivity that grapheme material is remarkable, makes Graphene barrier layer directly and P Pad is formed and is conductively connected, and simplifies structure and preparation technology, can improve efficiency.

Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses this practicality new Type.Multiple amendment to these embodiments will be apparent from for those skilled in the art, is determined herein The General Principle of justice can realize in the case of without departing from spirit or scope of the present utility model in other embodiments.Cause This, this utility model is not intended to be limited to embodiment illustrated herein, and is to fit to and principles disclosed herein and new The widest range that grain husk feature is consistent.

Claims (4)

1. a LED flip chip, including: substrate, the epitaxial layer being formed on described substrate, it is formed on described epitaxial layer Reflecting layer, described epitaxial layer includes p-type gallium nitride layer, luminescent layer and n type gallium nitride layer, it is characterised in that:

Being formed with Graphene barrier layer on described reflecting layer, N lead-in wire electrode is formed at and runs through described Graphene barrier layer, reflection Layer, p-type gallium nitride layer, luminescent layer until n type gallium nitride layer surface N electrode hole in；

The exposed surface of described epitaxial layer, the exposed surface on Graphene barrier layer, the exposed upper of substrate and N electrode hole and N Gap between lead-in wire electrode is formed with insulating barrier, and described insulating barrier is formed N pad and P pad, the described N of mutually insulated Pad is formed with N lead-in wire electrode and is conductively connected, and described P pad is formed with Graphene barrier layer and is conductively connected.

2. LED flip chip as claimed in claim 1, it is characterised in that: the exposed surface on described Graphene barrier layer is formed Having P lead-in wire electrode, described insulating barrier is formed at outside the exposed surface of described epitaxial layer, P the lead-in wire exposed surface of electrode, substrate Gap between dew upper surface and N electrode hole and N lead-in wire electrode, described P pad is stopped with Graphene by described P lead-in wire electrode Layer is formed and is conductively connected.

3. LED flip chip as claimed in claim 1 or 2, it is characterised in that: described Graphene barrier layer is completely covered reflection The exposed surface of layer.

4. LED flip chip as claimed in claim 1, it is characterised in that: described Graphene barrier layer is single or multiple lift stone Ink alkene.