CN102769043A

CN102769043A - Schottky diode and manufacturing method thereof

Info

Publication number: CN102769043A
Application number: CN201110114210XA
Authority: CN
Inventors: 胡佳贤
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-05-04
Filing date: 2011-05-04
Publication date: 2012-11-07

Abstract

The invention relates to a schottky diode and a manufacturing method of the schottky diode. The schottky diode comprises a first conduction type substrate and a first conduction type epitaxial layer, wherein a part of the area at the upper surface of the first conduction type epitaxial layer is etched so as to be groove-shaped; the etching depth is about 0.01-15 micrometers. A second conduction type protecting ring extends towards the first conduction type epitaxial layer. A dielectric material is formed on the epitaxial layer; one part of the dielectric material is removed so that one part of the protecting ring and one part of the epitaxial layer on the protecting ring are exposed; a conductive material is formed on the exposed parts on the upper surface of the epitaxial layer, namely the side wall and the bottom of the groove; and moreover a conductive material contacting with a substrate is formed at the bottom of the first conduction type substrate. According to the schottky diode, , only two layers of mask models are needed in the manufacturing process to form the device; compared with the traditional schottky diode manufacturing technology which has three layers of mask models, the schottky diode provided by the invention is reduced in the number of the mask models, so that the manufacturing cost is reduced, and meanwhile the production period is shortened; in addition, for a low voltage schottky diode, the positive breakover voltage drop and the breakover resistance can be reduced effectively.

Description

A kind of Schottky diode and preparation method thereof

Technical field

The present invention relates to technical field of semiconductor device, relate in particular to a kind of Schottky diode and preparation method thereof.

Background technology

Schottky diode is to utilize metal to contact the device that potential barrier is carried out work with semiconductor; Because advantages such as low, the reverse resume speed of its forward voltage drop is fast; Quilt is extensively in fields such as Switching Power Supply, solar energy, power electronics; Especially in recent years along with the development of new forms of energy, energy-saving low-carbon industry, the application of Schottky diode is increasing, and market scale constantly enlarges.

For diode, the power consumption during forward conduction is one of its topmost index; And the principal element of decision diode power consumption is its conduction voltage drop or conducting resistance; Schottky diode is compared with the PN junction diode, and its forward voltage drop, conducting resistance are lower, so power consumption is littler during forward conduction, therefore is widely used;

Be illustrated in figure 1 as the most frequently used Schottky diode structure at present; Comprise the first conductive type semiconductor material substrate 102; And first top 101, one on the conductive type semiconductor material epitaxy layer is formed at the second conduction type guard ring 103 in first conductive type epitaxial layer; Guard ring 103 tops and epitaxial loayer part surface form silicide material 104, the dielectric material 105 that zone, epitaxial loayer top covers; Be coated with the first metal layer 107 on silicide material and the part dielectric material, but connection electrode 109; Be coated with second metal level 106 in first conductive type semiconductor material substrate bottom, but connection electrode 108.

The manufacturing process of traditional this Schottky diode of manufacturing, like Fig. 2 to shown in Figure 9,

Mainly comprise:

The disk of 102 epitaxial loayers 101 at the bottom of the belt material is provided;

Whole former surface generates dielectric layer, covers photoresist 110 in the above, uses the ground floor mask plate to carry out 103 photoetching of the second conduction type guard ring, etching dielectric layer; Carrying out ion injects; Remove photoresist, heat-treat, on guard ring 103, can generate dielectric layer once more during heat treatment to form required guard ring 103; But thickness is littler than former dielectric layer, promptly has step;

Cover photoresist 110, use second layer mask plate to carry out photoetching, form required window, the etching dielectric layer comes out the part on epitaxial loayer 101 surfaces; Remove photoresist.

A high-melting point metal layer 111, like platinum, cover dielectric layer 105, guard ring and the epitaxial loayer 101 that comes out on; High melting point metal layer 111 is heated, thereby forms silicide 104 in the part that said high melting point metal layer contacts with epitaxial loayer 101; The high-melting point metal that is fit to can be platinum, tungsten, titanium, nickel, cobalt etc.;

Whole surface coverage metal level 107 covers photoresist 110, uses the tri-layer masking plate to carry out photoetching, and part metals layer 107 is etched; Remove photoresist;

The substrate bottom is handled, and like back face metalization, deposited metal 108 is drawn as electrode.

Know from above-mentioned, make this Schottky diode and need 3 layers of mask altogether.

For semiconductor chip, determine the factor of its cost to have a lot, like chip area, mask quantity, rate of finished products etc.; And wherein, mask quantity is one of topmost factor of several decision costs, therefore if can reduce the quantity of making required mask, just can reduce cost greatly; Simultaneously,, therefore also shortened the production cycle, can improve the performance of enterprises greatly because the minimizing of mask quantity has reduced manufacturing process.

Summary of the invention

The invention provides a kind of Schottky diode, comprising: the first conductive type semiconductor material drift layer on the first conductive type semiconductor material substrate and surface thereof; Its surperficial subregion of said drift layer is formed groove; Be formed at the second conductive type semiconductor material guard ring in the said drift layer, guard ring is arranged near the said drift layer of sidewall of groove; A kind of silicide material is formed at recess surface area; A kind of dielectric material is covered in said drift layer surface; The first metal layer is covered in said silicide material and dielectric material surface; Second metal level is covered in the said first conductive type semiconductor material substrate lower surface.

Its preparation method comprises: the first conductive type semiconductor material substrate surface providing forms the first conductive type semiconductor material drift layer; Form one deck dielectric material on the drift layer surface; Use the ground floor mask to remove dielectric material in groove surfaces to be formed; Carrying out second conductive type impurity on the first exposed conductive type semiconductor material drift layer surface mixes and heat treatment; Remove the dielectric material of groove surfaces to be formed, carry out the semi-conducting material corrosion and form groove; Heat-treat once more; Remove the groove surfaces dielectric material, cover metal, carry out sintering process and form silicide material in groove surfaces in groove surfaces; Cover metal material, use second layer mask to carry out metal etch; Use back metal technology, form backplate.

Schottky diode provided by the invention forms schottky barrier junction at the groove first conductive type semiconductor material surface, and near the second conductive type semiconductor material guard ring surface recess sidewall forms ohmic contact; Schottky diode is exactly the rectification characteristic work that utilizes schottky barrier junction; Guard ring wraps up concave corner simultaneously, can effectively reduce the electric field strength of corner, reduces leakage current; Simultaneously, when concave corner is in PROCESS FOR TREATMENT, possibly not form silicide material, but owing to formed ohmic contact in recess sidewall or bottom, so this does not exert an influence to device performance.What be worth explanation is that if concave corner is relatively slicker and more sly, guard ring can not wrap up concave corner.

Simultaneously Schottky diode of the present invention owing to adopted groove, has shortened the thickness of the drift region of schottky barrier junction, therefore on device performance, can effectively reduce conducting resistance, thus the power consumption when reducing forward conduction.

Preparation method of the present invention can effectively reduce mask quantity, reduces to 2 layers of mask from 3 layers of traditional mask, just can reduce cost greatly; Simultaneously,, therefore also shortened the production cycle, can increase the benefit greatly because the minimizing of mask quantity has reduced manufacturing process.

Description of drawings:

Fig. 1 is traditional Schottky diode structure generalized section;

Fig. 2 is the structural profile sketch map of the starting stage of the technology of manufacturing conventional schottky;

Fig. 3 is the generalized section of the Schottky diode structure shown in Figure 2 of next fabrication stage;

Fig. 4 is the generalized section of the Schottky diode structure shown in Figure 3 of next fabrication stage;

Fig. 5 is the generalized section of the Schottky diode structure shown in Figure 4 of next fabrication stage;

Fig. 6 is the generalized section of the Schottky diode structure shown in Figure 5 of next fabrication stage;

Fig. 7 is the generalized section of the Schottky diode structure shown in Figure 6 of next fabrication stage;

Fig. 8 is the generalized section of the Schottky diode structure shown in Figure 7 of next fabrication stage;

Fig. 9 is the generalized section of the Schottky diode structure shown in Figure 8 of next fabrication stage;

Figure 10 is a Schottky diode structure generalized section of the present invention;

Figure 11 is the starting stage structural profile sketch map of Schottky diode manufacturing process of the present invention;

Figure 12 is the generalized section of the Schottky diode structure shown in Figure 11 of next fabrication stage;

Figure 13 is the generalized section of the Schottky diode structure shown in Figure 12 of next fabrication stage;

Figure 14 is the generalized section of the Schottky diode structure shown in Figure 13 of next fabrication stage;

Figure 15 is the generalized section of the Schottky diode structure shown in Figure 14 of next fabrication stage;

Figure 16 is the generalized section of the Schottky diode structure shown in Figure 15 of next fabrication stage;

Figure 17 is the generalized section of the Schottky diode structure shown in Figure 16 of next fabrication stage;

Figure 18 is the generalized section of the Schottky diode structure shown in Figure 17 of next fabrication stage;

Figure 19 is the generalized section of the Schottky diode structure shown in Figure 180 of next fabrication stage;

Embodiment

Figure 10 is a Schottky diode structure generalized section of the present invention, specifies Schottky diode of the present invention below in conjunction with Figure 10.

Shown in figure 10; Schottky diode of the present invention comprises: the first conductive type semiconductor material drift layer 1 on the first conductive type semiconductor silicon materials substrate 2 and surface thereof; Substrate 2 is phosphorus doping density 0.001 Ω * cm, and drift layer 1 phosphorus doping resistivity is 10 Ω * cm thickness, 20 μ m; Said drift layer 1 its surperficial subregion is formed groove, and the degree of depth is 2 μ m; Be formed at the second conductive type semiconductor silicon materials guard ring 3 in the said drift layer, guard ring 3 is arranged near the said drift layer 1 of sidewall of groove, and guard ring 3 junction depths are 3 μ m; A kind of silicide material 4 is formed at recess surface area; A kind of dielectric material silica 5 is covered in said drift layer surface; The first metal layer TiNiAg7 is covered in said silicide material 4 and dielectric material surface 5, for device is drawn anode 9; The second metal level TiNiAg6 is covered in the said first conductive type semiconductor material substrate lower surface, for device is drawn negative electrode 8.

Its preparation method may further comprise the steps, like Fig. 2 to shown in Figure 9: the first conductive type semiconductor silicon materials substrate, the 2 surperficial epitaxial growth first conductive type semiconductor material drift layers 1 that providing; Form one deck dielectric material oxide layer 5 in the oxidation of drift layer surface heat; Carry out photoetching corrosion and remove dielectric material oxide layer 5 in groove surfaces to be formed; Carry out the second conductive type impurity boron on the exposed first conductive type semiconductor silicon materials drift layer, 1 surface and mix and heat treatment, thereby form guard ring 3; The dielectric material oxide layer 5 of the groove surfaces that erosion removal is to be formed is carried out the semi-conducting material dry etching and is formed groove; Heat-treat once more, make the corner of guard ring 3 parcel grooves; Erosion removal groove surfaces dielectric material oxide layer 5 covers metal Ni61 in groove surfaces,, carry out sintering process and form silicide material 4 in groove surfaces.Cover metal material the first metal layer TiNiAg7, use second layer mask to carry out metal etch; Use back metal technology, form the second metal level TiNiAg6.

The foregoing description enforcement of the present invention appearance attitude that only is used for giving an example, and set forth technical characteristic of the present invention, be not to be used for limiting category of the present invention.Any be familiar with this operator can unlabored change or the arrangement of the isotropism scope that all belongs to the present invention and advocated, interest field of the present invention should be as the criterion with claim.

Claims

1. Schottky diode comprises:

The first conductive type semiconductor material drift layer on the first conductive type semiconductor material substrate and surface thereof;

Its surperficial subregion of said drift layer is formed groove;

Be formed at the second conductive type semiconductor material guard ring in the said drift layer, guard ring is arranged near the said drift layer of sidewall of groove;

A kind of silicide material is formed at recess surface area;

A kind of dielectric material is covered in said drift layer surface;

The first metal layer is covered in said silicide material and dielectric material surface;

Second metal level is covered in the said first conductive type semiconductor material substrate lower surface.

2. Schottky diode according to claim 1 is characterized in that, the described first conduction type drift layer, and its surperficial subregion is formed groove, about 0.1 micron to 15 microns of depth of groove, depth of groove is less than drift layer thickness.

3. Schottky diode according to claim 1 is characterized in that, the described second conduction type guard ring extends internally about 0.1 micron to 15 microns from the surface of said drift layer.

4. Schottky diode according to claim 1 is characterized in that, the surf zone of described groove forms silicide material, and specifically, the drift layer surf zone in bottom portion of groove and side forms silicide material.

5. Schottky diode according to claim 1 is characterized in that, below a part of zone of the silicide material of described bottom portion of groove, does not have the second conduction type guard ring.

6. Schottky diode according to claim 1 is characterized in that, described dielectric material is positioned at the non-groove part of drift layer surface.

7. Schottky diode according to claim 1; It is characterized in that; Described the first metal layer is covered on said silicide material and the dielectric material; Contact with the surface of whole or a part of silicide material, described the first metal layer contacts with whole or a part of dielectric materials simultaneously.

8. the preparation method of Schottky diode according to claim 1 is characterized in that, may further comprise the steps:

First conductive type semiconductor material substrate surface providing forms the first conductive type semiconductor material drift layer;

Form one deck dielectric material on the drift layer surface;

Removal is at the dielectric material of groove surfaces to be formed;

Carrying out second conductive type impurity on the first exposed conductive type semiconductor material drift layer surface mixes and heat treatment;

Remove the dielectric material of groove surfaces to be formed, carry out the semi-conducting material corrosion and form groove;

Heat-treat once more;

Remove the groove surfaces dielectric material, cover metal, carry out sintering process and form silicide material in groove surfaces in groove surfaces.