CN207068868U

CN207068868U - A kind of silicon based gallium nitride power device

Info

Publication number: CN207068868U
Application number: CN201720735791.1U
Authority: CN
Inventors: 王静辉; 杨私私; 李晓波; 袁凤坡; 白欣娇
Original assignee: TONGHUI ELECTRONICS Corp CO Ltd
Current assignee: TONGHUI ELECTRONICS Corp CO Ltd
Priority date: 2017-06-23
Filing date: 2017-06-23
Publication date: 2018-03-02
Anticipated expiration: 2027-06-23

Abstract

A kind of silicon based gallium nitride power device is the utility model is related to, belongs to gallium nitride power device arts, including substrate, cushion and epitaxial layer, substrate is the 290km of curvature 280^‑1Silicon, it can solve the problem that the chip warpage problem that mismatch big between silicon substrate and gallium nitride is brought, cushion is the compound buffer layer of 50nm thickness, it includes at least one composite bed, composite bed is stacked and formed from down to up by AlN layers and GaN layer, cushion can effectively reduce the stress in epitaxial process, reduce the generation of extension crackle, recessed figure is etched with cushion, epitaxial layer is the GaN epitaxial layer of 200nm thickness, its upper end is provided with the AlGaN epitaxial layers of 300nm thickness, alleviation and thermal mismatch problem of the structure to silicon based gallium nitride material lattice mismatch problems are overcome with good effect, the performance and yields of the gallium nitride epitaxial materialses prepared in silicon base can be increased substantially, preparation for silicon based gallium nitride device provides technical support.

Description

A kind of silicon based gallium nitride power device

Technical field

The utility model belongs to gallium nitride power device arts, and in particular to a kind of silicon based gallium nitride power device.

Background technology

Characteristic of the gallium nitride power device due to gallium nitride material in itself, relative to silicon semiconductor leading in the market Power device, under same operating voltage and power condition, about 30%- can be further reduced in conversion process of energy 50% energy loss, while its volume is only the 1/10 of existing silicon semiconductor power device, operating voltage is higher, is higher than 600V, conversion is more powerful, and faster, more than 50MHz, all these advantages can reduce cost to working frequency, and change into Huge economic benefit, be advantageous to energy-saving.

The core of gallium nitride power device technology is the gallium nitride material for how producing high quality, because gallium nitride material Material fusing point itself is high, so being difficult to adopt the crystallization technique (such as silicon) of melting.Current state-of-the-art crystallization technique can only also give birth to 2 cun of pieces of output, cost is extremely expensive, can not realize large-scale production, so not possessing industrialization economic benefit demand.Present industry The technology of preparing of boundary's development comparative maturity and be provided simultaneously with commercial viability is metal-organic chemical vapor deposition equipment (MOCVD) epitaxy technology.Because the characteristic of gallium nitride material lattice, nature also lacks one and can matched with gallium nitride crystal lattice Similar and relatively low manufacturing cost backing material, the substrate generally used now are carborundum, sapphire and monocrystalline Silicon, with the progress of recent domestic SiC single crystal material preparation technology, the price of SiC single crystal substrate gradually reduces, and this is drop The production cost that gallium nitride epitaxial materialses are prepared in low SiC substrates creates condition, but SiC substrates and GaN material are normal in lattice All there is larger difference in number and thermal coefficient of expansion, thus can run into both sides problem：(1) lattice mismatch issue：Because of GaN crystalline substance Lattice constant (a=0.3189nm, c=0.5185nm) and 6H-SiC lattice constant (a=0.3073nm, c=1.0053nm) are no Together, 3.77% lattice mismatch causes that very big lattice mismatch stress can be produced initial stage in GaN epitaxial layer epitaxial growth, when The thickness of the GaN epitaxial layer of growth exceed a certain critical thickness (several nm to hundreds of nm are thick, it is specific regard the intermediate layer situation that introduces and It is fixed) after, this Macrolattice mismatch stress accumulated in GaN epitaxial layer will be in the form of producing dislocation and defect in interface Release, this is by the deterioration for causing GaN epitaxial layer crystalline quality and then reduces the performance of follow-up LED device structure；(2) thermal mismatching is asked Topic：Because of GaN thermal coefficient of expansion (a：5.59 × 10-6K) and 6H-SiC thermal coefficient of expansion (a：3.54 × 10-6K) there is also Larger difference, this causes GaN epitaxial layer or LED device structure to drop to room temperature from very high growth temperature (such as 800~1100 DEG C) During can gather very big thermal stress, this thermal stress is a kind of tensile stress for GaN epitaxial layer and then easily caused GaN epitaxial layer material produces cracking or bending, using the larger hot tensile stress of accumulation and has crackle or the GaN epitaxial layer material of bending LED component is prepared, the raising of LED component performance and yields certainly will be influenceed.Prepared in transfer at present and coordination release SiC substrates The common method of mismatch stress of GaN epitaxial layer material have：Stress covariant layer (including cushion, flexible layer, insert layer etc.) And graph substrate.Existing stress covariant layer, such as low temperature GaN buffer, AlN cushions, AlGaN component-gradient buffer layers, thin InAlGaN flexible layers etc., although there are better effects in terms of shifting and coordinating release lattice mismatch stress, shifting and assisting Effect is limited in terms of adjusting release thermal mismatch stress.

Utility model content

The utility model provides a kind of silicon based gallium nitride power device, and the device architecture is to silicon based gallium nitride material lattice The alleviation of mismatch problems and overcoming with good effect for thermal mismatch problem, can increase substantially the nitridation prepared in silicon base The performance and yields of gallium epitaxial material, the preparation to silicon based gallium nitride device provide technical support.

Concrete technical scheme of the present utility model is：

A kind of silicon based gallium nitride power device, including substrate, cushion and the epitaxial layer set gradually from down to up, close Key point is that described substrate is curvature 280-290km^-1Silicon, cushion is the compound buffer layer of 40-60nm thickness, compound slow Rushing layer includes at least one composite bed, and composite bed is stacked and formed from down to up by AlN layers and GaN layer, and decorations are carved in cushion upper surface Have a recessed figure, the depth of recessed figure is less than buffer layer thickness, epitaxial layer include 180-220nm thickness GaN epitaxial layer and The AlGaN epitaxial layers of the 280-320nm thickness of its upper end.

AlN layers and the thickness of GaN layer increase successively in described composite bed.

Described buffer layer thickness is 50nm, and GaN epitaxial layer thickness is 200nm, and AlGaN epitaxy layer thickness is 300nm.

The recessed figure of described cushion upper surface includes at least one of hole shape or bar shaped, and all recessed Figure is in periodic arrangement.

Recessed figure forms the cylindricality in periodic arrangement protruded after carving decorations in described cushion.

The beneficial effects of the utility model are：Curvature 280-290km is used in the utility model^-1Silicon as substrate, solve The chip warpage problem that mismatch big between silicon substrate and gallium nitride is brought, buffer layer structure energy between substrate and epitaxial layer The stress in epitaxial process is enough effectively reduced, the generation of extension crackle is reduced, recessed figure, epitaxial growth is etched on cushion When, the migration of atom needs the regular hour in recessed graphics field, so being not easy to be nucleated, film layer is while longitudinal growth Also cross growth is carried out, with the growth of thick film, adjacent cross growth region can reach merging, when cross growth reaches one Epitaxial layer of gallium nitride just can cover whole buffer-layer surface after determining degree, can be with using longitudinal growth and the merging of cross growth Reduce or suppress extension of the dislocation in epitaxial layer of gallium nitride, so as to improve the crystal mass of epitaxial layer of gallium nitride, epitaxial film materials Yields significantly improve therewith.

Brief description of the drawings

Fig. 1 is the structural representation of the utility model embodiment 1.

Fig. 2 is the top view of cushion in Fig. 1.

Fig. 3 is the structural representation of the utility model embodiment 2.

In accompanying drawing, 1, substrate, 2, cushion, 3, GaN epitaxial layer, 4, recessed figure, 5, AlGaN epitaxial layers.

Embodiment

The utility model is related to a kind of silicon based gallium nitride power device, including set gradually from down to up substrate 1, buffering Layer 2 and epitaxial layer, described substrate 1 are curvature 280-290km^-1Silicon, cushion 2 be 40-60nm thickness composite buffering Layer, compound buffer layer include at least one composite bed, and composite bed is stacked and formed from down to up by AlN layers and GaN layer, cushion 2 upper surfaces are carved and are decorated with recessed figure 4, and the depth of recessed figure 4 is less than the thickness of cushion 2, and epitaxial layer includes 180-220nm thickness GaN epitaxial layer 3 and its upper end 280-320nm thickness AlGaN epitaxial layers 5.

Embodiment 1, as depicted in figs. 1 and 2, silicon is used as substrate 1, the curvature 280-290km of substrate 1^-1, solve existing silicon The chip warpage problem that big mismatch is brought between substrate and gallium nitride, cushion 2 are the compound buffer layer of 50nm thickness, are covered In silicon monocrystalline substrate 1, compound buffer layer includes multiple composite beds, and composite bed is by AlN layers and GaN layer stacked group from down to up Into, and AlN thickness degree<GaN layer thickness, the upper surface of cushion 2 have the recessed figure of at least one of hole shape or bar shaped 4, all recessed figures 4 are in periodic arrangement, and as an example, recessed figure is through ICP for the recessed figure of the present embodiment optional holes shape Etch on cushion 2, the recessed depth of figure 4 is less than the thickness of cushion 2, and all hole shape rectangular array form arrangements, this is multiple Closing cushion has more preferable stress transfer compared to existing stress covariant layer technology and coordinates releasing effect, is mainly reflected in as follows Aspect：

1) AlN is selected, what its half insulation can improve compound buffer layer prevents electric leakage ability；From GaN layer, itself and GaN Epitaxial layer wellability is good, is advantageous to GaN nucleating growths.

The a shaft lattice constants of A1N materials are between GaN and silicon, and lattice mismatch is about 2% between GaN；Cube The lattice mismatch in TiN (111) faces and 6H-SiC (002) face is 2.22%, and the lattice mismatch with six-port technology (0002) face is 3.45%.

Based on compliant substrate can covariant intermediate layer stress transfer thought, in GaN epitaxy growth course, silicon substrate Coordinate to release in the compound buffer layer that lattice mismatch stress between GaN material just transfers to AlN layers and GaN layer combines Put.

GaN layer grows GaN epitaxial layer category isoepitaxial growth, and wellability is good, and GaN epitaxy thickness is uniform.

The AlN layers and the alternating stacked configuration of GaN layer that the present invention uses, the more multiple solutions of introducing play prevention and worn below again Saturating dislocation breeds the effect of extension upwards, so as to further reduce dislocation density；

2) end face ICP is etched with recessed figure 4 on the buffer layer 2, and recessed figure 4 is hole shape, is grown using pendeo-epitaxy The GaN epitaxial layer of technology growth 200nm thickness, in the AlGaN layer of epitaxial layer upper surface growth 300nm thickness, epitaxial growth, Using longitudinal growth and the merging of cross growth, it can reduce or suppress extension of the dislocation in GaN epitaxial layer, so as to improve GaN The crystal mass of epitaxial layer.

Embodiment 2, as shown in figure 3, another form as recessed figure 4, recessed figure 4 can form one after etching The cylindricality of group protrusion, i.e., the surface area outside the cylindricality of all protrusions are recessed figure 4, the rectangular battle array of cylindricality of all protrusions Row form is arranged.

The structure for the silicon based gallium nitride power device introduced in the utility model is to existing silicon based gallium nitride material lattice The alleviation of mismatch problems and overcoming with good effect for thermal mismatch problem, can increase substantially the nitridation prepared in silicon base The performance and yields of gallium epitaxial material, basis is done for the preparation of silicon based gallium nitride device, is adapted to application and marketing.

Claims

1. a kind of silicon based gallium nitride power device, including substrate (1), cushion (2) and the extension set gradually from down to up Layer, it is characterised in that：Described substrate (1) is curvature 280-290km^-1Silicon, cushion (2) is compound for 40-60nm thickness Cushion, compound buffer layer include at least one composite bed, and composite bed is stacked and formed from down to up by AlN layers and GaN layer, buffering Layer (2) upper surface, which is carved, is decorated with recessed figure (4), and the depth of recessed figure (4) is less than cushion (2) thickness, and epitaxial layer includes The AlGaN epitaxial layers (5) of the GaN epitaxial layer (3) of 180-220nm thickness and its 280-320nm thickness of upper end.

A kind of 2. silicon based gallium nitride power device according to claim 1, it is characterised in that：AlN in described composite bed Layer and the thickness of GaN layer increase successively.

A kind of 3. silicon based gallium nitride power device according to claim 1, it is characterised in that：Described cushion (2) is thick It is 200nm to spend for 50nm, GaN epitaxial layer (3) thickness, and AlGaN epitaxial layers (5) thickness is 300nm.

A kind of 4. silicon based gallium nitride power device according to claim 1, it is characterised in that：On described cushion (2) The recessed figure (4) of end face includes at least one of hole shape or bar shaped, and all recessed figures (4) are in periodically row Row.

A kind of 5. silicon based gallium nitride power device according to claim 1, it is characterised in that：In described cushion (2) Recessed figure (4) forms the cylindricality in periodic arrangement protruded after carving decorations.