CN103972306A - Schottky device structure with discontinuous grooves and manufacturing method of Schottky device structure - Google Patents
Schottky device structure with discontinuous grooves and manufacturing method of Schottky device structure Download PDFInfo
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 25
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 51
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 51
- 239000010703 silicon Substances 0.000 claims abstract description 51
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 43
- 229910052751 metal Inorganic materials 0.000 claims abstract description 36
- 239000002184 metal Substances 0.000 claims abstract description 36
- 238000000034 method Methods 0.000 claims abstract description 29
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910021332 silicide Inorganic materials 0.000 claims abstract description 22
- 238000013461 design Methods 0.000 claims description 49
- 229920005591 polysilicon Polymers 0.000 claims description 42
- 239000000758 substrate Substances 0.000 claims description 17
- 238000009826 distribution Methods 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 238000003491 array Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- 229910052697 platinum Inorganic materials 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 230000005484 gravity Effects 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 235000012239 silicon dioxide Nutrition 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910052721 tungsten Inorganic materials 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- 239000007769 metal material Substances 0.000 claims description 4
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- 238000009776 industrial production Methods 0.000 abstract description 3
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- 229910000510 noble metal Inorganic materials 0.000 description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 230000033001 locomotion Effects 0.000 description 5
- 230000005684 electric field Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
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- 238000009792 diffusion process Methods 0.000 description 2
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- XRZCZVQJHOCRCR-UHFFFAOYSA-N [Si].[Pt] Chemical compound [Si].[Pt] XRZCZVQJHOCRCR-UHFFFAOYSA-N 0.000 description 1
- UGACIEPFGXRWCH-UHFFFAOYSA-N [Si].[Ti] Chemical compound [Si].[Ti] UGACIEPFGXRWCH-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- QKJXFFMKZPQALO-UHFFFAOYSA-N chromium;iron;methane;silicon Chemical compound C.[Si].[Cr].[Fe] QKJXFFMKZPQALO-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66083—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
- H01L29/6609—Diodes
- H01L29/66143—Schottky diodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
- H01L29/861—Diodes
- H01L29/872—Schottky diodes
- H01L29/8725—Schottky diodes of the trench MOS barrier type [TMBS]
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- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
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- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
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Abstract
The invention provides a Schottky device structure with discontinuous grooves and a manufacturing method of the Schottky device structure. The Schottky device structure comprises a Schottky junction face distributed in a network state and multiple island-shaped groove structures distributed on the Schottky junction face in a grid array. The Schottky junction face is composed of an N-type light doped silicon epitaxial layer and metal silicide. The island-shaped groove structures comprise the grooves formed in the N-type light doped silicon epitaxial layer, dielectric layers formed on the surfaces of the grooves and polycrystalline silicon layers arranged in the grooves in a filled mode. According to the structure, the total area of the grooves is reduced to the maximum extent, the effective area of a groove-type Schottky device is maximized, under the condition that reverse electric leakage and reverse voltage-resistant properties are not reduced, forward voltage drop is reduced to the maximum extent, and resistance to surge image of the device is improved. The Schottky device structure and the manufacturing method are simple, cost is not increased, and the structure and method are suitable for industrial production.
Description
Technical field
The present invention relates to power device and field of microelectronic fabrication, particularly relate to a kind of schottky device structure with discontinuous trench design and preparation method thereof.
Background technology
Along with the development of semiconductor technology, power device, as a kind of new device, is widely used in the field such as disk drive, automotive electronics.Power device needs to bear larger voltage, electric current and power termination.And the devices such as existing MOS transistor cannot meet the demand, therefore, in order to meet the needs of application, various power devices become the focus of concern.
Schottky diode is generally to be noble metal (gold, silver, aluminium, platinum etc.) as anodal, taking N type semiconductor as negative pole, utilizes the potential barrier forming on the two contact-making surface to have rectification characteristic and the metal-semiconductor device made.Because exist a large amount of electronics in N type semiconductor, in noble metal, only there is the free electron of minute quantity, so electronics just spreads from the high N type semiconductor of concentration in the low noble metal of concentration.Obviously, in noble metal, there is no hole, just do not exist yet hole from metal the diffusion motion to N type semiconductor.Along with electronics is constantly diffused into noble metal from N type semiconductor, N type semiconductor surface electronic concentration reduces gradually, and surface electrical neutrality is destroyed, so just form potential barrier, its direction of an electric field is N type semiconductor → noble metal.But under this electric field action, the electronics in noble metal also can produce the drift motion from noble metal → N type semiconductor, thereby has weakened the electric field forming due to diffusion motion.When setting up behind the space charge region of certain width, the electron drift motion electrons spread motions that cause different from concentration that electric field causes reach relative balance, have just formed Schottky barrier.Schottky diode is a kind of low-power consumption, ultra-speed semiconductor device.Outstanding feature is reverse recovery time extremely short (may diminish to several nanoseconds), and forward conduction voltage drop is low.It is multiplex makes high frequency, low pressure, large current commutates diode, fly-wheel diode, protection diode, is also used in the circuit such as microwave communication and makes rectifier diode, small-signal detector diode uses.More common in communication power supply, frequency converter etc.
Power schottky device is a kind of semiconductor two terminal device for large current commutates, conventional power schottky device is made by the schottky junction between metal silicide and low-doped N-type silicon at present, and metal silicide can be platinum silicon compound, titanium-silicon compound, nickel-silicon compound and chrome-silicon compound etc.In recent years, due to the development of trench technique, various slot type structures are used to the earth leakage protective ring of production unit Schottky junction structure, the groove type MOS structure of employing as usual etc.
Groove-shaped Schottky diode: etching groove is as earth leakage protective ring around plane schottky junction, and by 0.5um to 50um not etc., trenched side-wall adopts thin gate oxide to gash depth, fills highly doped polysilicon and form MOS structural defence ring in groove.In power-type trench schottky diode, be current channel by the island schottky junction array parallel connection of being protected by MOS structure groove conventionally.Island schottky junction can be rectangle, circle, and polygon and strip, circular arc, these grooves form continuous network-like conventionally in whole device aspect, as shown in Figure 1 or 2.
For power-type trench schottky diode, schottky junction face array could provide current channel as effective area, so will improve the electric current traffic capacity in the device of given area as far as possible, should increase schottky junction area as far as possible, reduce the area that groove takies;
For the epitaxial wafer of given parameters, realize the object that improves reverse breakdown voltage, as shown in Figure 2, in island schottky junction there is maximum to the distance B of channel boundary in any point, exceedes this value and can cause electric leakage to increase withstand voltage decline; And the minimum dimension S of groove exists minimum value, lower than can causing MOS structure not form, this value causes component failure.Thereby restrict the ratio of effective area.
Summary of the invention
The shortcoming of prior art in view of the above, the object of the present invention is to provide a kind of schottky device structure with discontinuous trench design and preparation method thereof, for the electric current handling capacity that effectively improves schottky device on a kind of basis keeping reverse leakage and reverse breakdown voltage performance not to reduce is provided, reduce device architecture and the implementation method of forward voltage drop.
For achieving the above object and other relevant objects, the invention provides a kind of schottky device structure with discontinuous trench design, described schottky device structure comprises the schottky junction face of network-like distribution and is grid array and is distributed in the multiple island groove structures in described schottky junction face; Described schottky junction face is that N-type lightly-doped silicon epitaxial loayer and metal silicide form; Described island groove structure comprises the groove that is formed in described N-type lightly-doped silicon epitaxial loayer, is formed at the dielectric layer of described flute surfaces and is filled in the polysilicon layer in described groove.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, described schottky device structure comprises:
N-type heavy doping substrate, its lower surface is formed with bottom electrode;
N-type lightly-doped silicon epitaxial loayer, is incorporated into described N-type heavy doping substrate top surface;
Metal silicide; Network-like distribution is formed at described N-type lightly-doped silicon epi-layer surface, to form schottky junction face;
Multiple island groove structures, comprise that being grid array is formed at the island groove in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer of described island flute surfaces, and is filled in the polysilicon layer in described island groove;
Top electrode, is formed at described metal silicide and island groove structure surface.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, also comprise at least one the annular ditch groove structure that is surrounded on described schottky device structure periphery, described annular ditch groove structure comprises the annular ditch groove being formed in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer on described annular ditch groove surface and is filled in the polysilicon layer in described annular ditch groove.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, described island groove structure is three square arrays, cubic array or six square arrays and distributes.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, the plan view shape of described island groove structure is arbitrary graphic, wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.
Further, the plan view shape of described island groove structure comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, the width of described island groove structure is 0.15 micron～10 microns, and the degree of depth is 0.2 micron～20 microns.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, described dielectric layer is silicon dioxide layer, and described polysilicon layer is heavily doped polysilicon layer.
As a kind of preferred version of the schottky device structure with discontinuous trench design of the present invention, the metal material that forms described metal silicide is Ti, Pt, Ni, Cr, W, Mo or Co.
The present invention also provides a kind of manufacture method of the schottky device structure with discontinuous trench design, comprises step:
1) provide N-type heavy doping substrate, surface forms N-type lightly-doped silicon epitaxial loayer thereon;
2) in described N-type lightly-doped silicon epitaxial loayer, form and be multiple island grooves that grid array distributes, form dielectric layer in each island flute surfaces, in each island groove, fill polysilicon layer, and unnecessary polysilicon and the dielectric layer in removal surface, form island groove structure, and expose described N-type lightly-doped silicon epi-layer surface;
3) form metal level in described N-type lightly-doped silicon epitaxial loayer, and form metal silicide by annealing process, to form the schottky junction face of network-like distribution;
4) form top electrode in described metal silicide and each island flute surfaces, form bottom electrode in described N-type heavy doping substrate lower surface.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, step 2) be also included in each island groove structure peripheral formation at least one be surrounded on the step of the annular ditch groove structure of each island groove structure; Described annular ditch groove structure comprises the annular ditch groove being formed in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer on described annular ditch groove surface and is filled in the polysilicon layer in described annular ditch groove.
Further, the annular ditch groove of described annular ditch groove structure, dielectric layer and polysilicon layer form with island groove, dielectric layer and the polysilicon layer of described island groove structure respectively simultaneously.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, step 2) in, described island groove is three square arrays, cubic array or six square arrays and distributes.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, step 2) in, the plan view shape of described island groove structure is arbitrary graphic, wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.
Further, the plan view shape of described island groove structure comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, step 2) described dielectric layer is the silicon dioxide layer that adopts thermal oxidation technology to form, thickness is 5～1000 nanometers; Described polysilicon layer is heavily doped polysilicon layer, and its ion doping concentration is 10
19～10
21/ cm
3.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, step 3) material of described metal level is Ti, Pt, Ni, Cr, W, Mo or Co.
As a kind of preferred version of the manufacture method of the schottky device structure with discontinuous trench design of the present invention, the resistivity of described N-type heavy doping substrate is not more than 0.01ohmcm, the resistivity of described N-type lightly-doped silicon epitaxial loayer is not less than 0.01ohmcm, and thickness is 2 microns～30 microns.
As mentioned above, the invention provides a kind of schottky device structure with discontinuous trench design and preparation method thereof, described schottky device structure comprises the schottky junction face of network-like distribution and is grid array and is distributed in the multiple island groove structures in described schottky junction face; Described schottky junction face is that N-type lightly-doped silicon epitaxial loayer and metal silicide form; Described island groove structure comprises the groove that is formed in described N-type lightly-doped silicon epitaxial loayer, is formed at the dielectric layer of described flute surfaces and is filled in the polysilicon layer in described groove.The present invention has reduced the groove gross area to greatest extent, the effective area of groove type power schottky device is maximized, in the situation that ensureing reverse leakage and oppositely withstand voltage properties does not reduce, reduce to greatest extent forward voltage drop and improved the tolerance of device to surge impact.Device architecture of the present invention and manufacture method are simple, do not increase cost, are applicable to industrial production.
Brief description of the drawings
Fig. 1～Fig. 2 is shown as the structural representation of groove-shaped Schottky diode of the prior art.
Fig. 3～Fig. 4 is shown as the structural representation of the schottky device structure with discontinuous trench design of the present invention, wherein, Fig. 4 is the plan structure schematic diagram with the schottky device structure of discontinuous trench design, and Fig. 3 is the structural representation of Fig. 4 at A-A ' section.
Fig. 5～Figure 12 is shown as the structural representation that the each step of manufacture method of the schottky device structure with discontinuous trench design of the present invention presents
Element numbers explanation
10 schottky junction faces
20 island groove structures
30 annular ditch groove structures
101 N-type lightly-doped silicon epitaxial loayers
102 metal silicides
The island groove of 201 island groove structures
The dielectric layer of 202 island groove structures
The polysilicon layer of 203 island groove structures
The annular ditch groove of 301 annular ditch groove structures
The dielectric layer of 302 annular ditch groove structures
The polysilicon layer of 303 annular ditch groove structures
401 N-type heavy doping substrates
402 top electrodes
403 bottom electrodes
Embodiment
Below, by specific instantiation explanation embodiments of the present invention, those skilled in the art can understand other advantages of the present invention and effect easily by the disclosed content of this specification.The present invention can also be implemented or be applied by other different embodiment, and the every details in this specification also can be based on different viewpoints and application, carries out various modifications or change not deviating under spirit of the present invention.
Refer to Fig. 3～Figure 12.It should be noted that, the diagram providing in the present embodiment only illustrates basic conception of the present invention in a schematic way, satisfy and only show with assembly relevant in the present invention in graphic but not component count, shape and size drafting while implementing according to reality, when its actual enforcement, kenel, quantity and the ratio of each assembly can be a kind of random change, and its assembly layout kenel also may be more complicated.
As shown in Fig. 3～Fig. 4, the present embodiment provides a kind of schottky device structure with discontinuous trench design, and described schottky device structure comprises the schottky junction face 10 of network-like distribution and is grid array and is distributed in the multiple island groove structures 20 in described schottky junction face 10; Described schottky junction face 10 forms for N-type lightly-doped silicon epitaxial loayer 101 and metal silicide 102; Described island groove structure 20 comprises the groove that is formed in described N-type lightly-doped silicon epitaxial loayer 101, is formed at the dielectric layer 202 of described flute surfaces and is filled in the polysilicon layer 203 in described groove.
As shown in Fig. 3～Fig. 4, wherein, Fig. 4 is the plan structure schematic diagram with the schottky device structure of discontinuous trench design, and Fig. 3 is the structural representation of Fig. 4 at A-A ' section.As shown in the figure, particularly, the schottky device structure with discontinuous trench design in the present embodiment comprises:
N-type heavy doping substrate 401, its lower surface is formed with bottom electrode 403;
N-type lightly-doped silicon epitaxial loayer 101, is incorporated into described N-type heavy doping substrate 401 upper surfaces;
Metal silicide 102; Network-like distribution is formed at described N-type lightly-doped silicon epitaxial loayer 101 surfaces, to form schottky junction face 10;
Multiple island groove structures 20, comprise that being grid array is formed at the island groove in described N-type lightly-doped silicon epitaxial loayer 101, is incorporated into the dielectric layer 202 of described island flute surfaces, and is filled in the polysilicon layer 203 in described island groove;
Top electrode 402, is formed at described metal silicide 102 and island groove structure 20 surfaces.
In the present embodiment, the plan structure of the described schottky device structure with discontinuous trench design also comprises at least one the annular ditch groove structure 30 that is surrounded on described schottky device structure periphery, described annular ditch groove structure 30 comprises the annular ditch groove 301 being formed in described N-type lightly-doped silicon epitaxial loayer 101, is incorporated into the dielectric layer 302 on described annular ditch groove 301 surfaces and is filled in the polysilicon layer 303 in described annular ditch groove.The terminal protection structure of the final schottky device structure with discontinuous trench design as the present embodiment of described annular ditch groove structure 30.Described annular ditch groove structure 30 can be one, can be also two arrangements of being separated by above, can determine according to demands such as the withstand voltage and integrated levels of device.Visible; compared with the groove-shaped design of the present invention and traditional devices; the array area of device forms with the island groove structure 20 separating by being linked to be network-like schottky junction face 10, has only used continuous annular ditch groove in the terminal protection district at device edge, has improved widely the effective area of device.
The material of described N-type heavy doping substrate 401 is silicon, and its resistivity is not more than 0.01ohmcm, and the resistivity of described N-type lightly-doped silicon epitaxial loayer 101 is not less than 0.01ohmcm, and thickness is 2 microns～30 microns.
Described island groove structure 20 is three square arrays, cubic array or six square arrays and distributes.In the present embodiment, described island groove structure 20 is square array column distribution in described N-type lightly-doped silicon epitaxial loayer 101, finally makes described schottky junction face 10 form network-like structure.
As example, the plan view shape of described island groove structure 20 is arbitrary graphic, and wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.Further, the plan view shape of described island groove structure 20 comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.In the present embodiment, the plan view shape of described island groove structure 20 is circular, and as shown in Figure 3, circular island groove can improve the smoothness of groove inside, improves the voltage endurance capability of device.In addition, the width of described island groove structure 20 is 0.15 micron～10 microns, and the degree of depth is 0.2 micron～20 microns, and in the present embodiment, the width of described island groove structure 20 is 2 microns, and the degree of depth is 3 microns.
Described dielectric layer is silicon dioxide layer, and thickness is 5～1000 nanometers, and described polysilicon layer is P type heavily doped polysilicon layer.
As example, the metal material that forms described metal silicide 102 is Ti, Pt, Ni, Cr, W, Mo or Co.In the present embodiment, the metal material that forms described metal silicide 102 is Ti.The metal multilayer films such as the material of described top electrode 402 can be Cu, Al etc., and in the present embodiment, the material of described top electrode 402 is Al, and the material of described bottom electrode 403 is Ti/Ni/Ag.
As shown in Fig. 5～Figure 12, the present embodiment also provides a kind of manufacture method of the schottky device structure with discontinuous trench design, comprises step:
As shown in Figure 5, first carry out step 1), N-type heavy doping substrate 401 is provided, surface forms N-type lightly-doped silicon epitaxial loayer 101 thereon.
As example, the material of described N-type heavy doping substrate 401 is silicon, and its resistivity is not more than 0.01ohmcm, and the resistivity of described N-type lightly-doped silicon epitaxial loayer 101 is not less than 0.01ohmcm, and thickness is 2 microns～30 microns.
As shown in Fig. 6～Fig. 9, then carry out step 2), in described N-type lightly-doped silicon epitaxial loayer 101, form and be multiple island grooves 201 that grid array distributes, form dielectric layer 202 in each island flute surfaces, in each island groove, fill polysilicon layer 203, and remove surface unnecessary polysilicon and dielectric layer, form island groove structure 20, and expose described N-type lightly-doped silicon epitaxial loayer 101 surfaces.In addition, this step be also included in each island groove structure 20 peripheral formation at least one be surrounded on the step of the annular ditch groove structure 30 of each island groove structure 20; Described annular ditch groove structure 30 comprises the annular ditch groove 301 being formed in described N-type lightly-doped silicon epitaxial loayer 101, is incorporated into the dielectric layer 302 on described annular ditch groove surface and is filled in the polysilicon layer 303 in described annular ditch groove.Further, the annular ditch groove 301 of described annular ditch groove structure 30, dielectric layer 302 and polysilicon layer 303 form with island groove 201, dielectric layer 202 and the polysilicon layer 203 of described island groove structure 20 respectively simultaneously.
Described island groove structure 20 is three square arrays, cubic array or six square arrays and distributes.In the present embodiment, described island groove structure 20 is square array column distribution in described N-type lightly-doped silicon epitaxial loayer 101.
As example, the plan view shape of described island groove structure 20 is arbitrary graphic, and wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.Further, the plan view shape of described island groove structure 20 comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.In the present embodiment, the plan view shape of described island groove structure 20 is circular, and as shown in Figure 3, circular island groove can improve the smoothness of groove inside, improves the voltage endurance capability of device.In addition, the width of described island groove structure 20 is 0.15 micron～10 microns, and the degree of depth is 0.5 micron～10 microns, and in the present embodiment, the width of described island groove structure 20 is 2 microns, and the degree of depth is 3 microns.
As example, the dielectric layer of described island groove structure 20 and annular ditch groove structure 30 is silicon dioxide layer, and thickness is 5～1000 nanometers; The polysilicon layer of described island groove structure 20 and annular ditch groove structure 30 is heavily doped polysilicon layer, and its ion doping concentration is 10
19～10
21/ cm
3.
As example, adopt back carving technology to remove the unnecessary polysilicon in surface.Certainly, this step also may be included in device surface and make interlayer dielectric layer, and opens the step of contact hole by photoetching process, and, expose N-type lightly-doped silicon epitaxial loayer 101 in the region that need to make schottky junction face 10.
As shown in figure 10, then carry out step 3), form metal level in described N-type lightly-doped silicon epitaxial loayer 101, and form metal silicide 102 by annealing process, to form the schottky junction face 10 of network-like distribution;
As example, adopt the method for deposition to form metal level in described N-type lightly-doped silicon epitaxial loayer 101, the material of described metal level is Ti, Pt, Ni, Cr, W, Mo or Co.In the present embodiment, the material of described metal level is Ti.
As shown in Figure 11～Figure 12, finally carry out step 4), form top electrode 402 in described metal silicide 102 and each island flute surfaces, form bottom electrode 403 in described N-type heavy doping substrate 401 lower surfaces.
As example, the material of described top electrode 402 can be Cu, Al etc., and in the present embodiment, the material of described top electrode 402 is Al.The metal multilayer films such as the Ti/Ni/Ag that described bottom electrode 403 is the alloying by deposition and annealing process formation.
It should be noted that, schottky device structure with discontinuous trench design of the present embodiment and preparation method thereof is not only applicable to trench schottky device structure, other types of devices being also suitable for, as PN (PIN)/Schottky mixed type diode etc.
As mentioned above, the invention provides a kind of schottky device structure with discontinuous trench design and preparation method thereof, described schottky device structure comprises the schottky junction face 10 of network-like distribution and is grid array and is distributed in the multiple island groove structures 20 in described schottky junction face 10; Described schottky junction face 10 forms for N-type lightly-doped silicon epitaxial loayer 101 and metal silicide 102; Described island groove structure 20 comprises the groove that is formed in described N-type lightly-doped silicon epitaxial loayer 101, is formed at the dielectric layer of described flute surfaces and is filled in the polysilicon layer in described groove.The present invention has reduced the groove gross area to greatest extent, the effective area of groove type power schottky device is maximized, in the situation that ensureing reverse leakage and oppositely withstand voltage properties does not reduce, reduce to greatest extent forward voltage drop and improved the tolerance of device to surge impact.Device architecture of the present invention and manufacture method are simple, do not increase cost, are applicable to industrial production.So the present invention has effectively overcome various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all can, under spirit of the present invention and category, modify or change above-described embodiment.Therefore, such as in affiliated technical field, have and conventionally know that the knowledgeable, not departing from all equivalence modifications that complete under disclosed spirit and technological thought or changing, must be contained by claim of the present invention.
Claims (18)
1. a schottky device structure with discontinuous trench design, is characterized in that:
Described schottky device structure comprises the schottky junction face of network-like distribution and is grid array and is distributed in the multiple island groove structures in described schottky junction face;
Described schottky junction face is that N-type lightly-doped silicon epitaxial loayer and metal silicide form;
Described island groove structure comprises the groove that is formed in described N-type lightly-doped silicon epitaxial loayer, is formed at the dielectric layer of described flute surfaces and is filled in the polysilicon layer in described groove.
2. the schottky device structure with discontinuous trench design according to claim 1, is characterized in that: described schottky device structure comprises:
N-type heavy doping substrate, its lower surface is formed with bottom electrode;
N-type lightly-doped silicon epitaxial loayer, is incorporated into described N-type heavy doping substrate top surface;
Metal silicide; Network-like distribution is formed at described N-type lightly-doped silicon epi-layer surface, to form schottky junction face;
Multiple island groove structures, comprise that being grid array is formed at the island groove in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer of described island flute surfaces, and is filled in the polysilicon layer in described island groove;
Top electrode, is formed at described metal silicide and island groove structure surface.
3. the schottky device structure with discontinuous trench design according to claim 1 and 2, it is characterized in that: also comprise at least one the annular ditch groove structure that is surrounded on described schottky device structure periphery, described annular ditch groove structure comprises the annular ditch groove being formed in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer on described annular ditch groove surface and is filled in the polysilicon layer in described annular ditch groove.
4. the schottky device structure with discontinuous trench design according to claim 1, is characterized in that: described island groove structure is three square arrays, cubic array or six square arrays and distributes.
5. the schottky device structure with discontinuous trench design according to claim 1, it is characterized in that: the plan view shape of described island groove structure is arbitrary graphic, wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.
6. the schottky device structure with discontinuous trench design according to claim 5, is characterized in that: the plan view shape of described island groove structure comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.
7. the schottky device structure with discontinuous trench design according to claim 1, is characterized in that: the width of described island groove structure is 0.15 micron～10 microns, and the degree of depth is 0.2 micron～20 microns.
8. the schottky device structure with discontinuous trench design according to claim 1, is characterized in that: described dielectric layer is silicon dioxide layer, described polysilicon layer is heavily doped polysilicon layer.
9. the schottky device structure with discontinuous trench design according to claim 1, is characterized in that: the metal material that forms described metal silicide is Ti, Pt, Ni, Cr, W, Mo or Co.
10. a manufacture method with the schottky device structure of discontinuous trench design, is characterized in that, comprises step:
1) provide N-type heavy doping substrate, surface forms N-type lightly-doped silicon epitaxial loayer thereon;
2) in described N-type lightly-doped silicon epitaxial loayer, form and be multiple island grooves that grid array distributes, form dielectric layer in each island flute surfaces, in each island groove, fill polysilicon layer, and unnecessary polysilicon and the dielectric layer in removal surface, form island groove structure, and expose described N-type lightly-doped silicon epi-layer surface;
3) form metal level in described N-type lightly-doped silicon epitaxial loayer, and form metal silicide by annealing process, to form the schottky junction face of network-like distribution;
4) form top electrode in described metal silicide and each island flute surfaces, form bottom electrode in described N-type heavy doping substrate lower surface.
The manufacture method of the 11. schottky device structures with discontinuous trench design according to claim 10, is characterized in that: step 2) be also included in each island groove structure peripheral formation at least one be surrounded on the step of the annular ditch groove structure of each island groove structure; Described annular ditch groove structure comprises the annular ditch groove being formed in described N-type lightly-doped silicon epitaxial loayer, is incorporated into the dielectric layer on described annular ditch groove surface and is filled in the polysilicon layer in described annular ditch groove.
The manufacture method of the 12. schottky device structures with discontinuous trench design according to claim 11, is characterized in that: annular ditch groove, dielectric layer and the polysilicon layer of described annular ditch groove structure forms with island groove, dielectric layer and the polysilicon layer of described island groove structure respectively simultaneously.
The manufacture method of the 13. schottky device structures with discontinuous trench design according to claim 10, is characterized in that: step 2) in, described island groove is three square arrays, cubic array or six square arrays and distributes.
The manufacture method of the 14. schottky device structures with discontinuous trench design according to claim 10, it is characterized in that: step 2) in, the plan view shape of described island groove structure is arbitrary graphic, wherein, through in the size of this arbitrary graphic center of gravity, minimum dimension and maximum sized ratio are between 1～100.
The manufacture method of the 15. schottky device structures with discontinuous trench design according to claim 14, is characterized in that: the plan view shape of described island groove structure comprises a kind of or combination in circle, rectangle, triangle and polygons more than five limits.
The manufacture method of the 16. schottky device structures with discontinuous trench design according to claim 10, is characterized in that: step 2) described dielectric layer is silicon dioxide layer, thickness is 5～1000 nanometers; Described polysilicon layer is heavily doped polysilicon layer, and its ion doping concentration is 10
19～10
21/ cm
3.
The manufacture method of the 17. schottky device structures with discontinuous trench design according to claim 10, is characterized in that: step 3) material of described metal level is Ti, Pt, Ni, Cr, W, Mo or Co.
The manufacture method of the 18. schottky device structures with discontinuous trench design according to claim 10, it is characterized in that: the resistivity of described N-type heavy doping substrate is not more than 0.01ohmcm, the resistivity of described N-type lightly-doped silicon epitaxial loayer is not less than 0.01ohmcm, and thickness is 2 microns～30 microns.
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| CN107195692A (en) * | 2017-05-09 | 2017-09-22 | 中航（重庆）微电子有限公司 | Trench schottky diode and preparation method thereof |
| CN108231913A (en) * | 2018-01-25 | 2018-06-29 | 江苏捷捷微电子股份有限公司 | The structure and its manufacturing method of a kind of trench schottky diode |
| CN113054039A (en) * | 2020-11-27 | 2021-06-29 | 龙腾半导体股份有限公司 | Trench type Schottky diode device structure based on cellular structure and manufacturing method |
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| CN103474348A (en) * | 2013-08-28 | 2013-12-25 | 中航（重庆）微电子有限公司 | Punch-through groove Schottky device structure and manufacturing method thereof |
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| US20030203533A1 (en) * | 2002-04-25 | 2003-10-30 | International Rectifier Corp. | Single mask trench fred with enlarged schottky area |
| CN101114670A (en) * | 2006-07-28 | 2008-01-30 | 松下电器产业株式会社 | Schottky barrier semiconductor device |
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| CN107195692A (en) * | 2017-05-09 | 2017-09-22 | 中航（重庆）微电子有限公司 | Trench schottky diode and preparation method thereof |
| CN108231913A (en) * | 2018-01-25 | 2018-06-29 | 江苏捷捷微电子股份有限公司 | The structure and its manufacturing method of a kind of trench schottky diode |
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