阅读说明：本技术 一种半导体欧姆接触结构 (A kind of semiconductor ohmic contact structure ) 是由 洪鹏达 高逸 洪鹏辉 洪宝璇 方小姣 陈奇芝 于 2019-08-13 设计创作，主要内容包括：本发明属于半导体工艺技术领域,公开了一种半导体欧姆接触结构,包括n型GaAs的半导体基层,以及在基层的两侧面上氧化成型的氧化层,还包括金属层,所述金属层由内至外依次设有四层,分别包括第一金属层、第二金属层、第三金属层和第四金属层,其中所述第一金属层与第二金属层组合形成初始接触层,且初始接触层、第三金属层和第四金属层的厚度均由内至外依次增加；其中所述第三金属层至少包括一层结构层；本发明利用初始接触层、第三金属层和第四金属层的设置,实现提高欧姆接触结构氧化层附着力和减小金属接触电阻目的,其中初始接触层由第一金属层与第二金属层组合而成,形成部分扩散的效果,从而达到提高附着力的目的。(The invention belongs to semiconductor process technique fields, disclose a kind of semiconductor ohmic contact structure, base semiconductor including N-shaped GaAs, and molding oxide layer is aoxidized on the two sides of base, it further include metal layer, the metal layer is successively arranged four layers from the inside to the outside, respectively include the first metal layer, second metal layer, third metal layer and the 4th metal layer, wherein the first metal layer combines to form initial contact layer with second metal layer, and the thickness of initial contact layer, third metal layer and the 4th metal layer successively increases from the inside to the outside；Wherein the third metal layer includes at least one layer of structure sheaf；The present invention utilizes the setting of initial contact layer, third metal layer and the 4th metal layer, it realizes and improves ohmic contact structure oxide layer adhesive force and reduction metal contact resistance purpose, wherein initial contact layer is composed of the first metal layer and second metal layer, the effect of part diffusion is formed, to achieve the purpose that improve adhesive force.)

1. a kind of semiconductor ohmic contact structure, the base semiconductor including N-shaped GaAs, and aoxidized on the two sides of base Molding oxide layer, it is characterised in that: further include metal layer, the metal layer is successively arranged four layers from the inside to the outside, respectively includes The first metal layer, second metal layer, third metal layer and the 4th metal layer, wherein the first metal layer and second metal layer group Conjunction forms initial contact layer, and the thickness of initial contact layer, third metal layer and the 4th metal layer successively increases from the inside to the outside.

2. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: in the initial contact layer Each thickness degree is 30-100 Ethylmercurichlorendimide.

3. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: the outermost third gold The thickness for belonging to layer and the 4th metal layer is 500-1000 Ethylmercurichlorendimide.

4. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: the first metal layer uses One of Ti, Pd or Pt.

5. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: the third metal layer is at least Using one of Ti, Pd or Pt.

6. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: the second metal layer and Four metal layers are all made of one of Au, Ti, Pt or Zn.

7. a kind of semiconductor ohmic contact structure according to claim 1, it is characterised in that: the oxidation in the oxide layer Object, which includes at least, Ga₂O₃。

8. a kind of semiconductor ohmic contact structure described in any claim in -5 according to claim 1, it is characterised in that: system Make to use one of evaporation, sputtering or plating when the metal layer.

Technical field

The invention belongs to semiconductor process technique fields, and in particular to a kind of semiconductor ohmic contact structure.

Background technique

In semiconductor science, the whether device system of the performance study to Semiconductor Physics and material or semiconductor It makes, metal and semiconductor contact with each other and play extremely important effect, and the quality of contact performance directly affects the matter of device The research of amount and material, physics.

Metals-semiconductor contacts are generally divided into two classes: one kind is the Xiao Tejie with rectified action, also known as Schottky gesture Build contact；Another kind of is the ohm knot of non-rectified action, also known as Ohmic contact.Usual semiconductor devices and for testing half The sample of conductor parameter is connected using Ohmic contact, the quality of Ohmic contact quality, the size of contact resistance and physics Adherence directly influences the performance indicators such as efficiency, gain and the switching speed of device.The Ohm characteristic of metal largely shadow The electrology characteristic quality of Chinese percussion instrument part, the index for measuring metal layer contact quality superiority and inferiority generally have contact resistance size and physics adhesion Property etc..The contact resistance of metal electrode and device is the smaller the better under normal circumstances, this just needs to realize good Ohmic contact, Europe Nurse contact performance is better, and contact resistivity is lower.Therefore in order to realize good ohm contact performance, select metal material, Material requested thickness and production method all become most important.

In the prior art, by taking the Ohmic contact of N-shaped GaAs an example, most common two kinds of contact structures are alloying metal class Ni/Au/Ge structure and non-alloyed metalloid Ti/Pt/Au structure:

(1) Ni/Au/Ge structure has good adhesion, but asks during production there are thermal stability is insufficient Topic, causes ohmic contact surface to will form pointed protrusion, influences ohm contact performance；

(2) Ti/Pt/Au structure can prevent penetrating for Au by TiAs layers or PtAs layers of molding in production, thus The problem of avoiding the formation of pointed protrusion, but outflowing in order to avoid electric current, usually plates one layer of gallium oxide in the side of GaAs Layer, specifically by taking structure shown in FIG. 1 as an example, is followed successively by base 10, oxide layer 11, Ti, Pt and Au from the inside to the outside, and in gallium oxide The evaporation of arsenic oxide arsenoxide causes to reduce with the As in conjunction with Ti/Pt during oxidation molding, thus make on side TiAs layers or PtAs layers of molding thickness reduces, and can not even be formed, greatly reduce integrally-built adhesion effect, lead to outermost layer Au Being formed by metal layer there are problems that being easy to fall off, and influence ohm contact performance.

Summary of the invention

In consideration of it, it is a kind of based on a kind of semiconductor ohmic contact structure it is necessary to propose, effectively to solve above-mentioned background skill The problem of being proposed in art, and reach the contact effect that adhesive force is strong, contact resistivity is low.

To achieve the above object, the invention provides the following technical scheme: a kind of semiconductor ohmic contact structure, including N-shaped The base semiconductor of GaAs, and molding oxide layer is aoxidized on the two sides of base, it further include metal layer, the metal layer It is successively arranged four layers from the inside to the outside, respectively includes the first metal layer, second metal layer, third metal layer and the 4th metal layer, Described in the first metal layer combine to form initial contact layer with second metal layer, and initial contact layer, third metal layer and the 4th The thickness of metal layer successively increases from the inside to the outside；Wherein the third metal layer includes at least one layer of structure sheaf.

Preferably, each thickness degree in the initial contact layer is 30-100 Ethylmercurichlorendimide.

Preferably, the thickness of the third metal layer and the 4th metal layer is 500-1000 Ethylmercurichlorendimide.

Preferably, the first metal layer is using one of Ti, Pd or Pt.

Preferably, the third metal layer at least uses one of Ti, Pd or Pt.

Preferably, the second metal layer and the 4th metal layer are using one of Au, Ti, Pt or Zn.

Compared with the prior art, the present invention has the following beneficial effects:

It combines to form initial contact layer with second metal layer by the first metal layer, wherein the first metal layer is in oxide layer table Face combines and forms thin protective layer, so that second metal layer has the effect of that part is spread；And it was both avoided that just based on part diffusion Beginning contact layer generates pointed protrusion in forming process, and can form accessory attachment layer, effectively improves the attached of initial contact layer Intensity, to further ensure the adhesion effect of whole ohmic contact structure；To sum up, so that ohm disclosed in this invention Contact structures have the advantages that adhesive force is strong；

In addition, successively adhere to third metal layer and the 4th metal layer in initial contact layer surface, wherein third metal layer Thickness is greater than initial contact layer, ensure that third metal layer has the effect of obstructing completely, and then improve the 4th metal layer Stability, and the contact resistivity of whole ohmic contact structure is reduced, so that using Ohmic contact knot provided by the present invention The electrology characteristic of the device of structure is also further improved.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of existing ohmic contact structure；

Fig. 2 is the structural schematic diagram of a preferred embodiment in the present invention；

Fig. 3 is the structural schematic diagram of another preferred embodiment in the present invention；

In figure: base 10, oxide layer 11, the first metal layer 12, second metal layer 13, third metal layer 14, the 4th metal Layer 15.

Specific embodiment

Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other Embodiment shall fall within the protection scope of the present invention.

It please refers to shown in Fig. 2-Fig. 3, the invention provides the following technical scheme: a kind of semiconductor ohmic contact structure, including n The base semiconductor 10 of type GaAs, and molding oxide layer 11 is aoxidized on the two sides of base 10, wherein in oxide layer 11 The oxide for mainly including has Ga₂O₃；

It further include the four layers of metal layer set gradually from the inside to the outside, respectively the first metal layer 12, second metal layer 13, Three metal layers 14 and the 4th metal layer 15, wherein the first metal layer 12 is respectively formed and connects with 10 top surface of base and 11 surface of oxide layer Touching；

Wherein the first metal layer 12 is using one of Ti, Pd or Pt, and third metal layer 14 is at least using in Ti, Pd or Pt One kind, second metal layer 13 and the 4th metal layer 15 are using one of Au, Ti, Pt or Zn；

Preferably, four layers of metal layer are all made of one of evaporation, sputtering or plating technique system when making molding Make.

First embodiment

Referring to shown in Fig. 2, and according to the structure of above-mentioned offer and the constituent material of counter structure, second metal layer is set 13 and the 4th metal layer 15 by taking Au as an example, the first metal layer 12 and third metal layer 14 are by taking Ti as an example, i.e., metal layer is in N-shaped Using from the successively Dagwood knot of titanium-gold-plating titanium (Ti/Au/Ti/Au) from the inside to the outside on the base semiconductor 10 of GaAs Structure:

Wherein, the thickness of the first metal layer 12 (Ti) and second metal layer 13 (Au) are 30 Ethylmercurichlorendimides, third metal layer 14 It (Ti) is 500 Ethylmercurichlorendimides with the thickness of the 4th metal layer 15 (Au)；

Specifically, the first metal layer 12 combines to form initial contact layer with second metal layer 13, and wherein the first metal layer 12 covers It is placed on 11 surface of 10 top surface of base and oxide layer, the part contacted with base 10 top surface directly infiltrates into base 10, so that Ti in the first metal layer 12 is mixed to form TiAs layers in base 10 with As；And second metal layer 13 is then covered in the first metal 12 surface of layer, and isolation effect is formed to it by the first metal layer 12, Au in second metal layer 13 is prevented to a certain extent Diffusion, but complete blocking cannot be formed, with this Au in second metal layer 13 partially be extended in base 10, herein It is not in a large amount of diffusions because of Au when thereby guaranteeing that initial contact formable layer in the process since Au only can be carried out part diffusion And the problem of generating pointed protrusion, influencing structural behaviour；In addition, for being covered in 11 surface portion of oxide layer, second Au in metal layer 13 equally generates part and spreads, and is infiltrated into oxide layer 11 with this, and the Ga combination shape in oxide layer 11 At AuGa layers, so that making the physical coherence of 10 outer wall of base enhances, be effectively ensured whole initial contact layer and base 10 it Between adhesion effect, and overall structure obtained by subsequent covering is made to all have stronger adhesive force, it is easy to fall off to avoid the occurrence of metal layer The problem of；

The surface of second metal layer 13 successively cladding thickness be 500 Ethylmercurichlorendimides third metal layer 14 and the 4th metal layer 15, wherein the molding thickness of third metal layer 14 can effectively meet the needs of obstructing completely, thus to Au in the 4th metal layer 15 Diffusion there is complete blocking effect, guarantee that the 4th metal layer 15 has complete and excellent contact, while the 4th metal layer 15 thickness itself also can effectively meet contact demand；To sum up, the superior electrical of Au in the 4th metal layer 15 can be made full use of Characteristic to achieve the effect that reduce the contact resistivity of whole ohmic contact structure, and makes using Europe provided by the present invention The electrology characteristic of the device of nurse contact structures is also further improved.

Second embodiment

Identical structure and examples of materials according to first embodiment:

Wherein the first metal layer 12 and the thickness of second metal layer 13 are 100 Ethylmercurichlorendimides, third metal layer 14 and the 4th gold medal The thickness for belonging to layer 15 is 1000 Ethylmercurichlorendimides.

3rd embodiment

Referring to shown in Fig. 3, and according to the structure of above-mentioned offer and the constituent material of counter structure, second metal layer is set 13 and the 4th metal layer 15 by taking Au as an example, the first metal layer 12 is by taking Ti as an example, and third metal layer 14 is then with the combination of Ti and Pt For, i.e., metal layer is on the base semiconductor 10 of N-shaped GaAs using from successively titanium-gold-plating titanium platinum (Ti/Au/ from the inside to the outside Ti/Pt/Au Dagwood structure):

Specifically, third metal layer 14 shown in Fig. 3 includes two structure sheafs of a/b, is wherein formed by Pt for a layers, b is by Ti shape At；

The thickness of the first metal layer 12 (Ti) and second metal layer 13 (Au) are 30 Ethylmercurichlorendimides, 14 (Ti/ of third metal layer It Pt is) 500 Ethylmercurichlorendimides with the thickness of the 4th metal layer 15 (Au).

Fourth embodiment

Identical structure and examples of materials according to 3rd embodiment:

Wherein the first metal layer 12 and the thickness of second metal layer 13 are 100 Ethylmercurichlorendimides, third metal layer 14 and the 4th gold medal The thickness for belonging to layer 15 is 1000 Ethylmercurichlorendimides, and third metal layer 14 is combined by two structure sheafs of a/b and formed.

It although an embodiment of the present invention has been shown and described, for the ordinary skill in the art, can be with A variety of variations, modification, replacement can be carried out to these embodiments without departing from the principles and spirit of the present invention by understanding And modification, the scope of the present invention is defined by the appended.