CN101901808A - Trench-type Schottky-barrier diode rectifier and preparation method - Google Patents
Trench-type Schottky-barrier diode rectifier and preparation method Download PDFInfo
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- CN101901808A CN101901808A CN 201010208588 CN201010208588A CN101901808A CN 101901808 A CN101901808 A CN 101901808A CN 201010208588 CN201010208588 CN 201010208588 CN 201010208588 A CN201010208588 A CN 201010208588A CN 101901808 A CN101901808 A CN 101901808A
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- 238000002360 preparation method Methods 0.000 title abstract 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 66
- 229910052751 metal Inorganic materials 0.000 claims abstract description 60
- 239000002184 metal Substances 0.000 claims abstract description 60
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 34
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 33
- 230000004888 barrier function Effects 0.000 claims description 45
- 235000012239 silicon dioxide Nutrition 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 27
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 22
- 239000000758 substrate Substances 0.000 claims description 20
- 238000000151 deposition Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 238000001312 dry etching Methods 0.000 claims description 12
- 230000008021 deposition Effects 0.000 claims description 11
- 238000001039 wet etching Methods 0.000 claims description 9
- 229920005591 polysilicon Polymers 0.000 claims description 7
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 229920002120 photoresistant polymer Polymers 0.000 claims description 6
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 6
- 239000002019 doping agent Substances 0.000 claims description 5
- 108090000723 Insulin-Like Growth Factor I Proteins 0.000 claims description 3
- 102000013275 Somatomedins Human genes 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 239000002131 composite material Substances 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 238000001259 photo etching Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 230000000903 blocking effect Effects 0.000 abstract description 9
- 230000000694 effects Effects 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052782 aluminium Inorganic materials 0.000 abstract description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 2
- 239000010936 titanium Substances 0.000 abstract description 2
- 229910052719 titanium Inorganic materials 0.000 abstract description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 230000005684 electric field Effects 0.000 description 4
- 238000005036 potential barrier Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
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Abstract
The invention provides a trench-type Schottky-barrier diode rectifier and a preparation method. By using the two shoulders of a conducting poly-silicon T-shaped head in the trench and the silica layers on the extended sections to cover the vertex angles of boss structures on two sides of the trench, the invention, based on the existing trench-type Schottky diode rectifiers, overcomes the problems of increase in inverse current leakage and reduction in inverse blocking capacity caused by the tip discharge effect produced by contact of the vertex angles of the boss and an upper metal layer; moreover, by filling the trench with the conducting poly-silicon instead of aluminum, titanium and other conventional materials of the upper metal layer, on one hand, the invention solves the problem that the reliability of the rectifier is influenced by hollow cavities left during trench filling, and on the other hand, the invention provides more flexible design space for the ratio of the opening width to depth of the trench of the diode rectifier.
Description
Technical field
The present invention relates to a kind of rectifying device and manufacture method thereof, particularly plough groove type metal-semiconductor Schottky-barrier diode rectifier and manufacture method.
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 weakness 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 that the present invention studies.
Summary of the invention
The invention provides a kind of channel schottky barrier diode rectifying device and manufacture method, its objective is and to improve existing channel schottky barrier diode rectifying device above shortcomings, further improve the performance of device.
For achieving the above object, the technical scheme that device architecture of the present invention 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.
For achieving the above object, the technical scheme that manufacture method of the present invention adopts is: a kind of manufacture method of channel schottky barrier diode rectifying device comprises following process steps:
The first step, on the N+ monocrystalline substrate of N type high-dopant concentration, growth N type is than the N-epitaxial loayer of low doping concentration;
In second step, at N-epitaxial loayer upper surface somatomedin layer, this dielectric layer 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 is implemented photoetching, define groove figure;
The 4th step, adopt dry etching method, selectivity is removed the dielectric layer of not protected by photoresist, exposes the N-epitaxial loayer of groove figure correspondence, and removes the dielectric layer 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 the N-epitaxial loayer zone that employing dry etching method selective etch exposes forms groove in the N-epitaxial loayer, the N-epitaxial loayer zone by the hard mask protection of medium between the groove forms N-monocrystalline silicon boss structure;
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 of medium greater than N-epitaxial loayer internal channel, 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 grooved inner surface and the groove top open part laterally evenly grows silicon dioxide layer;
In the 8th step, at total upper surface depositing electrically conductive polysilicon, conductive polycrystalline silicon fills up the surface and has the groove of silicon dioxide layer and the open space of groove top;
The 9th step, conductive polycrystalline silicon 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 the N-epitaxial loayer end face, make the cross section of the conductive polycrystalline silicon that the groove position remains T-shaped;
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 the N-monocrystalline silicon boss structure end face on the N-epitaxial loayer expose to the open air out;
The 11 step, metal level on total upper surface deposition, should go up metal level and contact the formation Schottky Barrier Contact with N-monocrystalline silicon boss structure end face on the N-epitaxial loayer, the T shape crown face and the contacts side surfaces that go up simultaneously metal level and conductive polycrystalline silicon form ohmic contact, and last metal level constitutes the anode of channel schottky barrier diode rectifying device;
In the 12 step, at the bottom surface of N+ monocrystalline substrate deposition lower metal layer, this 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.
Related content in the technique scheme is explained as follows:
1. in the above-mentioned device architecture 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 above-mentioned device architecture scheme, described " T shape head " refers to the horizontal stripe structure at T shape top.
Because the technique scheme utilization, the present invention compared with prior art has following advantage and effect:
1. the present invention is by the improvement of device architecture design and manufacture method; 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, and wherein the left side curve is from structure of the present invention, 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 present invention can make reverse leakage reduce about 38% as can be seen.
2. the present invention's 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, the dissatisfied trench fill of having determined 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 embodiment of the invention 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 embodiment of the invention 2 groove-type Schottky diode rectifying devices.
Accompanying drawing 5 is the simulation curve comparison diagram of reverse leakage current of the present invention and reverse voltage relation.
Accompanying drawing 6A～6E is a manufacture craft schematic flow sheet of the present invention.
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 present invention is further described:
Embodiment 1: a kind of channel schottky barrier diode rectifying device and manufacture method
As shown in Figures 2 and 3, channel schottky barrier diode rectifying device structure of the present invention 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 present invention's 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, manufacture method of the present invention 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: a kind of channel schottky barrier diode rectifying device and manufacture method
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 invention and characteristics, and its purpose is to allow the personage who is familiar with this technology can understand content of the present invention and enforcement according to this, can not limit protection scope of the present invention with this.All equivalences that spirit is done according to the present invention change or modify, and all should be encompassed within protection scope of the present invention.
Claims (2)
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.
2. manufacture method according to the described channel schottky barrier diode rectifying device of claim 1 is characterized in that comprising following process steps:
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 layer (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) figure;
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 correspondence, 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 regional monocrystalline silicon of N-epitaxial loayer (2) that adopts the dry etching method selective etch to expose, form groove (3) in N-epitaxial loayer (2), N-epitaxial loayer (2) zone by the hard mask protection of medium between the groove (3) forms N-monocrystalline silicon boss structure (4);
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 of medium (3) 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 surface 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 groove (3) that the surface has silicon dioxide layer (5) and the open space of groove (3) top;
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 face, make the cross section of the conductive polycrystalline silicon (11) that groove (3) position remains T-shaped;
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 face on the N-epitaxial loayer (2) expose to the open air out;
The 11 step, metal level (6) on total upper surface deposition, should go up metal level (6) and contact formation Schottky Barrier Contact (7) with N-monocrystalline silicon boss structure (4) end face 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 device;
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.
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| CN2010102085881A CN101901808B (en) | 2010-06-23 | 2010-06-23 | Trench-type Schottky-barrier diode rectifier and preparation method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103035751A (en) * | 2012-11-23 | 2013-04-10 | 上海华虹Nec电子有限公司 | Schottky diode |
| CN106449774A (en) * | 2016-10-11 | 2017-02-22 | 扬州扬杰电子科技股份有限公司 | Groove-type barrier schottky structure for optimizing electric field on surface and manufacturing method of groove-type barrier schottky structure |
| CN107785256A (en) * | 2016-08-31 | 2018-03-09 | 无锡华润上华科技有限公司 | Semiconductor devices and preparation method thereof |
| CN111883527A (en) * | 2020-07-10 | 2020-11-03 | 安徽安芯电子科技股份有限公司 | Groove type Schottky barrier chip for manufacturing large-size wafer |
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| JPS61212060A (en) * | 1985-03-18 | 1986-09-20 | Hitachi Ltd | Schottky barrier diode |
| US5365102A (en) * | 1993-07-06 | 1994-11-15 | North Carolina State University | Schottky barrier rectifier with MOS trench |
| CN1591798A (en) * | 2003-07-10 | 2005-03-09 | 国际整流器公司 | Process for forming thick oxides on si or sic for semiconductor devices |
| CN201725794U (en) * | 2010-06-23 | 2011-01-26 | 苏州硅能半导体科技股份有限公司 | Groove type schottky barrier diode rectifying device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103035751A (en) * | 2012-11-23 | 2013-04-10 | 上海华虹Nec电子有限公司 | Schottky diode |
| CN107785256A (en) * | 2016-08-31 | 2018-03-09 | 无锡华润上华科技有限公司 | Semiconductor devices and preparation method thereof |
| CN106449774A (en) * | 2016-10-11 | 2017-02-22 | 扬州扬杰电子科技股份有限公司 | Groove-type barrier schottky structure for optimizing electric field on surface and manufacturing method of groove-type barrier schottky structure |
| CN111883527A (en) * | 2020-07-10 | 2020-11-03 | 安徽安芯电子科技股份有限公司 | Groove type Schottky barrier chip for manufacturing large-size wafer |
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| CN101901808B (en) | 2011-11-09 |
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