CN201725794U - Groove type schottky barrier diode rectifying device - Google Patents
Groove type schottky barrier diode rectifying device Download PDFInfo
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- CN201725794U CN201725794U CN2010202360070U CN201020236007U CN201725794U CN 201725794 U CN201725794 U CN 201725794U CN 2010202360070 U CN2010202360070 U CN 2010202360070U CN 201020236007 U CN201020236007 U CN 201020236007U CN 201725794 U CN201725794 U CN 201725794U
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Abstract
The utility model relates to a groove type schottky barrier diode rectifying device. On the basis of the existing groove type schottky barrier diode rectifying device, the groove type schottky barrier diode rectifying device utilizes two shoulders of a conducting polysilicon T-shaped head in a groove and a silicon dioxide layer at an extending section to shield boss-structured top corners at the two sides of the groove and further the problems that the boss-structured top corners and an upper metal layer are contacted to generate point discharge effect so as to cause increasing of reverse leakage and decreasing of reverse blocking capability. In addition, the conducting polysilicon is adopted to replace the materials of aluminium, titanium and the like of the conventional upper metal layer to fill the groove, therefore, on one hand, the problem that holes are left in filling of the groove to influence the reliability of the device is solved, and on the other hand, more flexible design space is provided for the ratio of the width and depth of an opening of the groove of the device.
Description
Technical field
The utility model relates to a kind of rectifying device, particularly plough groove type metal-semiconductor Schottky-barrier diode rectifier.
Background technology
Rectifying device requires unidirectional on state characteristic as the switching device of AC-to DC, and promptly cut-in voltage is low during forward conduction, and conducting resistance is little, and blocking voltage height oppositely the time, reverse leakage is little.
Schottky diode has used many decades in the application of power field as rectifying device.For the PN junction diode, Schottky diode has the low and fast advantage of switching speed of forward cut-in voltage, and this makes it be fit to very much be applied to Switching Power Supply and high frequency occasion.The reverse recovery time of Schottky diode is very short, and this time is mainly determined by the parasitic capacitance of device, and determines by lacking sub-recombination time unlike the PN junction diode.Therefore, the Schottky diode rectifying device can effectively reduce the switch power loss.
Schottky diode is that the metal-semiconductor junction principle of utilizing metal to contact formation with semiconductor is made.The silicon chip of traditional plane Schottky diode is made of the N+ substrate of the high-dopant concentration that is positioned at the below and the N-epitaxially grown layer of the low doping concentration that is positioned at the top usually, the N+ substrate bottom surface deposition lower metal layer of high-dopant concentration forms ohmic contact, constitutes the negative electrode of Schottky diode; The N-epitaxially grown layer end face deposition of low doping concentration goes up metal level and forms Schottky contacts, constitutes the anode of Schottky diode.The work function difference of metal and n type single crystal silicon forms potential barrier, and the height of this potential barrier has determined the characteristic of Schottky diode, and promptly lower potential barrier can reduce the forward conduction cut-in voltage, but reverse leakage is increased, and reverse blocking voltage reduces; Otherwise higher potential barrier can increase the forward conduction cut-in voltage, and reverse leakage is reduced, and reverse blocking capability strengthens.Yet, to compare with the PN junction diode, traditional plane Schottky diode reverse leakage is big, and reverse blocking voltage is low.
When channel schottky barrier diode rectifying device has the low forward conduction cut-in voltage, overcome the shortcoming of above-mentioned plane Schottky diode.U.S. Pat 5,365,102 have disclosed a kind of channel schottky barrier diode rectifying device and manufacture method, wherein the device architecture of an embodiment (Fig. 1 is equivalent to Fig. 6 F of United States Patent (USP)) as shown in Figure 1.As can be seen from the figure, the silicon chip of making device is made of highly doped N+ substrate 1 and more low-doped N-epitaxial loayer 2, a series of grooves 3 are prepared in the N-epitaxial loayer 2, it between the groove 3 n type single crystal silicon boss structure 4, the growth of groove 3 sidewalls has silicon dioxide layer 5, last metal level 6 covers the upper surface of total, and contacts formation Schottky contacts face 7 with the end face of monocrystalline silicon boss structure 4, constitutes the anode of Schottky diode rectifying device.Deposit the negative electrode of lower metal layer 8 formation Schottky diode rectifying devices in N+ substrate 1 bottom surface.This patent is just because of the existence of metal in groove 3 and the groove 3, and Electric Field Distribution changes when making the device reverse bias, and the electric field strength that arrives Schottky barrier reduces, thereby has strengthened the voltage reversal blocking ability of this device, has reduced reverse leakage.Yet the shortcoming that this structural design exposed is: 1. because boss drift angle 9 directly contacts with last metal level 6, have point discharge effect (the radius of curvature introductory note plays electric field strength and increases), cause that easily reverse leakage becomes big, reverse blocking capability descends; 2. in manufacture process, because the silicon dioxide layer 5 local damages easily of boss drift angle 9 sides directly contact boss drift angle 9 sides, thereby cause reverse leakage to become big with last metal level 6, reverse blocking capability descends; 3. the metals of filling in the groove 3 are identical with last metal level 6, and the slit filling capacity owing to last metal level 6 materials when groove 3 width are narrower is bad, might stay the cavity, influences the reliability of device.For this reason, how addressing the above problem is the problem of the utility model research.
Summary of the invention
The utility model provides a kind of channel schottky barrier diode rectifying device, its objective is to improve existing channel schottky barrier diode rectifying device above shortcomings, further improves the performance of device.
For achieving the above object, the technical scheme that the utility model device adopts is: a kind of channel schottky barrier diode rectifying device, and on top plan view, the active area of this device is made of several Schottky barrier diode unit cell parallel connections; Passing through on the longitudinal cross-section at Schottky barrier diode unit cell center, each Schottky barrier diode unit cell is from bottom to top by lower metal layer, the N+ monocrystalline substrate, N-epitaxial loayer and the stack of last metal level constitute, wherein on described N-epitaxial loayer top, the lateral separation offers groove, N-epitaxial loayer zone between two adjacent trenches forms N-monocrystalline silicon boss structure, boss structure end face and last metal layer contacting form Schottky Barrier Contact, last metal level constitutes the anode of channel schottky barrier diode rectifying device, lower metal layer contacts with the N+ monocrystalline substrate and forms ohmic contact, and lower metal layer constitutes the negative electrode of channel schottky barrier diode rectifying device.
Its innovation is: grooved inner surface evenly growth has silicon dioxide layer, and silicon dioxide layer laterally extends to form the extension to both sides at the groove top open part, the extension silicon dioxide layer covers the drift angle of boss structure, filled conductive polysilicon in the groove, the cross section of conductive polycrystalline silicon is T-shaped, T shape head height is in N-epitaxial loayer end face, two shoulder transverse widths of T shape head are greater than the transverse opening width of groove, two shoulders of T shape head ride on the silicon dioxide layer of extension, make two shoulders and the extension silicon dioxide layer of T shape head cover the boss structure drift angle of groove both sides, the end face of T shape head and side and last metal layer contacting form ohmic contact.
Related content in the technique scheme is explained as follows:
1. in the such scheme, " several " in described " active area is made of several Schottky barrier diode unit cell parallel connections " in quantity implication for more than at least two.
2. in the such scheme, described " T shape head " refers to the horizontal stripe structure at T shape top.
Because the technique scheme utilization, the utility model compared with prior art has following advantage and effect:
1. the utility model is by the device architecture design improvement; utilize two shoulders and the extension silicon dioxide layer of conductive polycrystalline silicon T shape head to cover the boss structure drift angle of groove both sides; the direct and last metal layer contacting of protection boss structure drift angle; thereby overcome point discharge effect (the radius of curvature introductory note plays electric field strength and increases), made device have the voltage reversal blocking ability of lower reverse leakage and Geng Gao electrically.Fig. 5 is the reverse current～reverse voltage curve comparison diagram of a Schottky barrier diode unit cell of software simulation; wherein the left side curve is from the utility model structure, and right side graph does not have the structure of silicon dioxide, polysilicon protection from monocrystalline silicon boss structure drift angle.Contrast from figure under the 30V reverse bias voltage, adopts the utility model can make reverse leakage reduce about 38% as can be seen.
2. the utility model filled conductive polycrystalline silicon material in groove, conventionally materials such as metal level aluminium, titanium have been replaced, comparatively speaking conductive polycrystalline silicon has stronger slit filling capacity, having solved trench fill stays the cavity on the one hand, influence the problem of device reliability, groove opening width and the depth scale for device provides more flexible design space for space on the other hand.
Description of drawings
Accompanying drawing 1 is a U.S. Pat 5,365, the profile of 102 embodiment devices.
Accompanying drawing 2 is the schematic top plan view of the utility model embodiment 1 groove-type Schottky diode rectifying device.
Accompanying drawing 3 is the A-A profile of Fig. 2.
Accompanying drawing 4 is the schematic top plan view of the utility model embodiment 2 groove-type Schottky diode rectifying devices.
Accompanying drawing 5 is the simulation curve comparison diagram of the utility model reverse leakage current and reverse voltage relation.
Accompanying drawing 6A～6E is the utility model manufacture craft schematic flow sheet.
In the above accompanying drawing: the 1.N+ monocrystalline substrate; 2.N-epitaxial loayer; 3. groove; 4. boss structure; 5. silicon dioxide layer; 6. go up metal level; 7. Schottky Barrier Contact; 8. lower metal layer; 9. boss drift angle; 10. dielectric layer; 11. conductive polycrystalline silicon.
Embodiment
Below in conjunction with drawings and Examples the utility model is further described:
Embodiment 1:
As shown in Figures 2 and 3, the utility model channel schottky barrier diode rectifying device structure is: (see figure 2) on top plan view, the active area of this device is made of several Schottky barrier diode unit cell parallel connections.Passing through (see figure 3) on the longitudinal cross-section at Schottky barrier diode unit cell center, each Schottky barrier diode unit cell is from bottom to top by lower metal layer 8, N+ monocrystalline substrate 1, N- epitaxial loayer 2 and 6 stacks of last metal level constitute, wherein on described N-epitaxial loayer 2 tops, the lateral separation offers groove 3, N-epitaxial loayer 2 zones between two adjacent trenches 3 form N-monocrystalline silicon boss structures 4, boss structure 4 end faces contact with last metal level 6 and form Schottky Barrier Contact 7, last metal level 6 constitutes the anode of channel schottky barrier diode rectifying device, lower metal layer 8 contacts with N+ monocrystalline substrate 1 and forms ohmic contact, and lower metal layer 8 constitutes the negative electrode of channel schottky barrier diode rectifying device.
As shown in Figure 3, the utility model innovation is: groove 3 inner surfaces evenly growth have silicon dioxide layer 5, and silicon dioxide layer 5 laterally extends to form the extension to both sides at groove 3 top open parts, extension silicon dioxide layer 5 covers the drift angle of boss structure 4, filled conductive polysilicon 11 in the groove 3, the cross section of conductive polycrystalline silicon 11 is T-shaped, T shape head height is in N-epitaxial loayer 2 end faces, two shoulder transverse widths of T shape head are greater than the transverse opening width of groove 3, two shoulders of T shape head ride on the extension silicon dioxide layer 5, make two shoulders and the extension silicon dioxide layer 5 of T shape head cover boss structure 4 drift angles of groove 3 both sides, the end face of T shape head contacts with last metal level 6 with the side and forms ohmic contact.
Based on above-mentioned rectifying device, the utility model manufacture method comprises following process steps:
Referring to Fig. 6 A:
The first step, on the N+ monocrystalline substrate 1 of N type high-dopant concentration, growth N type is than the N-epitaxial loayer 2 of low doping concentration;
In second step, at N-epitaxial loayer 2 upper surface somatomedin layers 10, this dielectric layer 10 is a silicon dioxide layer, perhaps silicon nitride layer, the perhaps composite bed of silicon dioxide layer and silicon nitride layer;
The 3rd step, dielectric layer 10 is implemented photoetching, define groove 3 figures (as can be seen from Figure 2 groove 3 figures are latticed);
The 4th step, adopt dry etching method, selectivity is removed the dielectric layer of not protected by photoresist 10, exposes the N-epitaxial loayer 2 of groove 3 figure correspondences, and removes the dielectric layer 10 that remains behind the photoresist as the hard mask of medium;
The 5th step, with the hard mask of medium as protection, the monocrystalline silicon in N-epitaxial loayer 2 zones that employing dry etching method selective etch exposes forms groove 3 in N-epitaxial loayer 2, N-epitaxial loayer 2 zones by the hard mask protection of medium between the groove 3 form N-monocrystalline silicon boss structures 4;
Referring to Fig. 6 B:
The 6th step, adopt wet etching method, the hard mask of selective removal part medium makes the transverse opening width of the transverse opening width of the hard mask respective grooves 3 of medium greater than N-epitaxial loayer 2 internal channel 3, simultaneously the reduced thickness of the hard mask of medium;
The 7th step, the total upper surface is carried out thermal oxidation, oxygen and monocrystalline silicon are reflected at groove 3 inner surfaces and the groove top open part laterally evenly grows silicon dioxide layer 5;
In the 8th step, at total upper surface depositing electrically conductive polysilicon 11, conductive polycrystalline silicon 11 fills up the surface and has the groove 3 of silicon dioxide layer 5 and the open space of groove 3 tops;
Referring to Fig. 6 C:
The 9th step, conductive polycrystalline silicon 11 to deposition is implemented dry etching, from up to down remove the conductive polycrystalline silicon on total surface, end face up to conductive polycrystalline silicon is lower than the hard mask end face of medium, be higher than simultaneously till N-epitaxial loayer 2 end faces, make the cross section of the conductive polycrystalline silicon 11 that groove 3 positions remain T-shaped;
Referring to Fig. 6 D:
The tenth step, the total upper surface is implemented wet etching, perhaps first dry etching is wet etching again, and selectivity is removed the hard mask of medium, makes N-monocrystalline silicon boss structure 4 end faces on the N-epitaxial loayer 2 expose to the open air out;
Referring to Fig. 6 E:
The 11 step, metal level 6 on total upper surface deposition, through Overheating Treatment (temperature and time is determined according to prior art), should go up metal level 6 and contact formation Schottky Barrier Contact 7 with N-monocrystalline silicon boss structure 4 end faces on the N-epitaxial loayer 2, the T shape crown face and the contacts side surfaces that go up simultaneously metal level 6 and conductive polycrystalline silicon 11 form ohmic contact, and last metal level 6 constitutes the anode of channel schottky barrier diode rectifying devices;
In the 12 step, at the bottom surface of N+ monocrystalline substrate 1 deposition lower metal layer 8, this lower metal layer 8 contacts with N+ monocrystalline substrate 1 and forms ohmic contact, and lower metal layer 8 constitutes the negative electrode of channel schottky barrier diode rectifying device.
Embodiment 2:
As shown in Figure 4, the difference of present embodiment and embodiment 1 is: from the top plan view of rectifying device, and the figure difference of groove 3, embodiment 1 is latticed, the Schottky barrier diode unit cell is the lattice of arranged in arrays.And the figure of present embodiment groove 3 as can be seen from Figure 4 is the strip that is parallel to each other, and the Schottky barrier diode unit cell is be parallel to each other rectangular.Other content is identical with embodiment 1, no longer is repeated in this description here.
By embodiment 1 and embodiment 2 as can be seen the top plan view layout and the shape of rectifying device unit cell other variations can be arranged, be shaped as prismatic, circle, triangle or the like such as unit cell, and layout can be big small circle ring from inside to outside.
The foregoing description only is explanation technical conceive of the present utility model and characteristics, and its purpose is to allow the personage who is familiar with this technology can understand content of the present utility model and enforcement according to this, can not limit protection range of the present utility model with this.All equivalences of being done according to the utility model spirit change or modify, and all should be encompassed within the protection range of the present utility model.
Claims (1)
1. channel schottky barrier diode rectifying device, on top plan view, the active area of this device is made of several Schottky barrier diode unit cell parallel connections; Passing through on the longitudinal cross-section at Schottky barrier diode unit cell center, each Schottky barrier diode unit cell is from bottom to top by lower metal layer (8), N+ monocrystalline substrate (1), N-epitaxial loayer (2) and last metal level (6) stack constitute, wherein on described N-epitaxial loayer (2) top, the lateral separation offers groove (3), N-epitaxial loayer (2) zone between two adjacent trenches (3) forms N-monocrystalline silicon boss structure (4), boss structure (4) end face contacts with last metal level (6) and forms Schottky Barrier Contact (7), last metal level (6) constitutes the anode of channel schottky barrier diode rectifying device, lower metal layer (8) contacts with N+ monocrystalline substrate (1) and forms ohmic contact, and lower metal layer (8) constitutes the negative electrode of channel schottky barrier diode rectifying device;
It is characterized in that: groove (3) inner surface evenly growth has silicon dioxide layer (5), and silicon dioxide layer (5) laterally extends to form the extension to both sides at groove (3) top open part, extension silicon dioxide layer (5) covers the drift angle of boss structure (4), the interior filled conductive polysilicon of groove (3) (11), the cross section of conductive polycrystalline silicon (11) is T-shaped, T shape head height is in N-epitaxial loayer (2) end face, two shoulder transverse widths of T shape head are greater than the transverse opening width of groove (3), two shoulders of T shape head ride on the extension silicon dioxide layer (5), make two shoulders and the extension silicon dioxide layer (5) of T shape head cover boss structure (4) drift angle of groove (3) both sides, the end face of T shape head contacts with last metal level (6) with the side and forms ohmic contact.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202360070U CN201725794U (en) | 2010-06-23 | 2010-06-23 | Groove type schottky barrier diode rectifying device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202360070U CN201725794U (en) | 2010-06-23 | 2010-06-23 | Groove type schottky barrier diode rectifying device |
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| Publication Number | Publication Date |
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| CN201725794U true CN201725794U (en) | 2011-01-26 |
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| CN2010202360070U Expired - Lifetime CN201725794U (en) | 2010-06-23 | 2010-06-23 | Groove type schottky barrier diode rectifying device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101901808A (en) * | 2010-06-23 | 2010-12-01 | 苏州硅能半导体科技股份有限公司 | Trench-type Schottky-barrier diode rectifier and preparation method |
| CN103378171A (en) * | 2012-04-28 | 2013-10-30 | 朱江 | Groove Schottky semiconductor device and preparation method thereof |
| GB2530284A (en) * | 2014-09-17 | 2016-03-23 | Anvil Semiconductors Ltd | High voltage semiconductor devices |
| CN108155223A (en) * | 2017-12-29 | 2018-06-12 | 福建龙夏电子科技有限公司 | Groove-shaped diode component and forming method thereof |
-
2010
- 2010-06-23 CN CN2010202360070U patent/CN201725794U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101901808A (en) * | 2010-06-23 | 2010-12-01 | 苏州硅能半导体科技股份有限公司 | Trench-type Schottky-barrier diode rectifier and preparation method |
| CN103378171A (en) * | 2012-04-28 | 2013-10-30 | 朱江 | Groove Schottky semiconductor device and preparation method thereof |
| CN103378171B (en) * | 2012-04-28 | 2017-11-14 | 朱江 | A kind of groove Schottky semiconductor device and preparation method thereof |
| GB2530284A (en) * | 2014-09-17 | 2016-03-23 | Anvil Semiconductors Ltd | High voltage semiconductor devices |
| US10157979B2 (en) | 2014-09-17 | 2018-12-18 | Anvil Semiconductors Limited | High voltage semiconductor device with reduced peak electric field in active and termination areas of the device |
| CN108155223A (en) * | 2017-12-29 | 2018-06-12 | 福建龙夏电子科技有限公司 | Groove-shaped diode component and forming method thereof |
| CN108155223B (en) * | 2017-12-29 | 2023-12-08 | 福建龙夏电子科技有限公司 | Trench diode device and forming method thereof |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20110126 Effective date of abandoning: 20120502 |