CN105576045A - Trench Schottky barrier diode and manufacturing method thereof - Google Patents
Trench Schottky barrier diode and manufacturing method thereof Download PDFInfo
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- 230000004888 barrier function Effects 0.000 title claims abstract description 100
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 239000002184 metal Substances 0.000 claims abstract description 53
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims abstract description 52
- 239000000758 substrate Substances 0.000 claims abstract description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 62
- 238000000407 epitaxy Methods 0.000 claims description 44
- 239000000377 silicon dioxide Substances 0.000 claims description 31
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 28
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 28
- 235000012239 silicon dioxide Nutrition 0.000 claims description 25
- 229920005591 polysilicon Polymers 0.000 claims description 22
- 238000000151 deposition Methods 0.000 claims description 15
- 230000008021 deposition Effects 0.000 claims description 15
- 238000001312 dry etching Methods 0.000 claims description 15
- 238000001259 photo etching Methods 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 8
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 238000005530 etching Methods 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
- 230000007246 mechanism Effects 0.000 claims description 3
- 229920002120 photoresistant polymer Polymers 0.000 claims description 3
- 230000026267 regulation of growth Effects 0.000 claims description 3
- 238000002955 isolation Methods 0.000 abstract description 7
- 229910021421 monocrystalline silicon Inorganic materials 0.000 abstract description 4
- 230000000903 blocking effect Effects 0.000 abstract description 3
- 230000005684 electric field Effects 0.000 description 17
- 239000000463 material Substances 0.000 description 10
- 238000005036 potential barrier Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 3
- 239000010970 precious metal Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
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- 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
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- 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
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
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- H—ELECTRICITY
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- 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
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
- H01L29/0603—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions
- H01L29/0607—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration
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- 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
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- 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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Abstract
The invention discloses a trench Schottky barrier diode. The trench Schottky barrier diode comprises an active region and a cut-off region, wherein the active region consists of a positive electrode metal layer, a Schottky barrier metal layer, a first conduction type lightly-doped N-type epitaxial layer, a first conduction type heavily-doped single crystal silicon substrate and a negative electrode metal layer from top to bottom in sequence; an upper part of the N-type epitaxial layer is provided with a plurality of trenches; the trenches are formed transversely at intervals; the Schottky barrier metal layer is in Schottky barrier contact with a top surface of the N-type epitaxial layer between adjacent trenches; the trenches are filled with conductive polycrystalline silicon; an isolation layer is arranged between the conductive polycrystalline silicon and the trenches; vacuum air gaps are formed inside the isolation layer; and the trenches are communicated in the active region and the cut-off region. The trench Schottky barrier diode has the advantages of high reverse blocking voltage, low reverse bias voltage, low reverse leakage current and the like. The invention also discloses a manufacturing method of the trench Schottky barrier diode. The manufacturing method has the advantages of less steps, low manufacturing cost and the like.
Description
Technical field
The invention belongs to technical field of semiconductors, especially relate to a kind of trench schottky barrier diode and manufacture method thereof.
Background technology
Schottky barrier diode is that the metal-semiconductor junction principle utilizing metal and semiconductor contact to be formed makes.The metal level that traditional planar type Schottky barrier diode device is deposited by N-type epitaxy layer and the end face of low doping concentration usually forms Schottky Barrier Contact and forms.The work function difference of metal and n type single crystal silicon forms potential barrier, and the height of this potential barrier determines the characteristic of Schottky barrier diode.Lower barrier height makes device reverse BV low, and reverse leakage is large, and forward conduction voltage drop is low; Higher barrier height then makes device reverse BV high, and reverse leakage is little, but forward conduction voltage drop is high.When device is in reverse bias, device inside electric field strength maximum is positioned at potential barrier near interface N-type epitaxy layer end face; Meanwhile, also there is barrier height and reduce effect, namely along with reverse bias voltage raises the phenomenon of barrier height reduction.Above-mentioned 2 this reverse leakage of device is increased rapidly along with reverse bias voltage raises, and finally cause device to puncture, seriously limit performance and the device reliability of planar type Schottky barrier diode.For the problems referred to above, trench schottky barrier diode is invented, and part overcomes the shortcoming of above-mentioned planar type Schottky barrier diode.
The distinguishing feature of trench schottky barrier diode is the trench gate that there is the arrangement of some cycles in N-type epitaxy layer, and the Schottky barrier that the metal level that N-type epitaxy layer and end face deposit is formed is present between trench gate.Described trench gate, by the groove extended in N-type epitaxy layer, covers the separator of flute surfaces, and the electric conducting material be connected with the metal level that end face deposits of filling wherein forms.A kind of trench schottky barrier diode as disclosed in US Patent No. 5365102 and manufacture method.
Due to the existence of the trench gate structure of cycle arrangement; when making device be in reverse bias, the maximum of internal electric intensity distribution and electric field strength all there occurs change: first; the position that in N-type epitaxy layer, electric field strength maximum occurs; near zone bottom N-type epitaxy layer body internal channel grid is transferred to by the end face of N-type epitaxy layer; N-type epitaxy layer between trench gate sidewall exhausts completely, makes the depleted layer protection of Schottky barrier.In addition, reverse bias voltage is shared by the separator in N-type epitaxy layer and trench gate structure, and the electric field strength in N-type epitaxy layer is reduced; According to the product of electric field strength in material and material relative dielectric constant in different material junctional interfaces place continuous print theorem, the ratio shared depends on the relative dielectric constant of N-type epitaxy layer and separator, separator relative dielectric constant is less, wherein electric field strength is larger, and the reverse bias voltage that separator is shared is larger.Maximum field intensity locations during reverse bias in N-type epitaxy layer does not appear at Schottky barrier area, this electric field strength reduces simultaneously, trench schottky barrier diode is made to inhibit barrier height to reduce effect, effectively reduce reverse leakage, device reverse BV ability and reliability have very large lifting.
As can be seen here, improve trench gate structure, make separator can share larger reverse bias voltage, reduce the electric field strength in N-type epitaxy layer, significant to further boost device Performance And Reliability.
Summary of the invention
The invention provides a kind of trench schottky barrier diode than prior art and have lower reverse leakage, better voltage reversal blocking ability, can bear higher reverse biased, the trench schottky barrier diode that reliability is better and cost is lower.
Present invention also offers a kind of manufacture method of trench schottky barrier diode, this manufacture method step is few, and low cost of manufacture achieves the trench gate structure of improvement, can effectively improve device performance and reliability.
For achieving the above object, the technical solution used in the present invention is as follows:
A kind of trench schottky barrier diode, comprise the active area at middle part and be surrounded with the cut-off region in source region, active area is made up of anode metal layer, schottky barrier metal layer, the lightly doped N-type epitaxy layer of the first conduction type, the heavily doped monocrystalline substrate of the first conduction type and cathode metal layer from top to bottom successively; N-type epitaxy layer top is provided with some grooves, and channel lateral interval is arranged; The end face of the N-type epitaxy layer between schottky barrier metal layer and adjacent trenches forms Schottky Barrier Contact; Be filled with conductive polycrystalline silicon in groove, the end face of conductive polycrystalline silicon and schottky barrier metal layer form ohmic contact; Be provided with separator between conductive polycrystalline silicon and groove, the inside of separator is provided with vacuum gap; Groove is interconnected in active area and cut-off region.
In separator, vacuum gap is provided with in the present invention, vacuum relative dielectric constant is 1, the relative dielectric constant of the N-type epitaxy layer obtained by monocrystalline silicon is 11.9, in foundation material, the product of electric field strength and material relative dielectric constant is in different material junctional interfaces place continuous print theorem, then the electric field strength in vacuum gap is 11.9 times of N-type epitaxy layer.Because vacuum has the minimum relative dielectric constant of known substance, so the electric field strength that the separator that inside is provided with vacuum gap is born is much larger than the simple separator using other non-conductive medium.Under same reverse bias condition, the separator that inside is provided with vacuum gap has shared higher reverse biased, the reverse biased born needed for N-type epitaxy layer and Schottky barrier effectively reduces, thus better inhibit barrier height to reduce effect, reduce device reverse leakage, improve device voltage reverse blocking capability, improve the reliability of device.The reverse biased born because of Schottky barrier is low, the schottky barrier metal layer that potential barrier is lower then can be used to open pressure drop to reduce device forward, improve device forward conduction characteristic, and in general, contained by the lower metal of potential barrier, precious metal ratios is low, therefore schottky barrier metal layer cost is low, can reduce the cost of whole device.
As preferably, separator is silicon dioxide layer.
As preferably, the width of vacuum gap is 10 ~ 1000.
As preferably, the vacuum degree of vacuum gap is 1 ~ 10
-6holder.
As preferably, vacuum gap has 1 ~ 10.
As preferably, the thickness of schottky barrier metal layer is 10 ~ 5000.
A manufacture method for Schottky barrier diode, comprises the following steps:
(1) in the heavily doped monocrystalline substrate of the first conduction type, the lightly doped N-type epitaxy layer of first kind conduction type is grown;
(2) adopt photoetching successively and be dry-etched in N-type epitaxy layer and etch groove;
(3) in the top layer growth regulation one silica layer of total;
(4) at the top layer growing polycrystalline silicon layer of total;
(5) the second silicon dioxide layer is grown at the top layer of total;
(6) at the top layer deposition conductive polycrystalline silicon of total, conductive polycrystalline silicon is full of groove;
(7) adopt dry etching selective removal partially conductive polysilicon, the end face of conductive polycrystalline silicon is flushed with the end face of N-type epitaxy layer;
(8) adopt dry etching selective removal part second silicon dioxide layer, the polysilicon layer making to be on the top of N-type epitaxy layer between adjacent trenches exposes to the open air out;
(9) at the top layer deposition silicon nitride layer of total;
(10) photoetching and dry etching is adopted to remove not by silicon nitride layer that photoresist is protected successively, the top layer of the conductive polycrystalline silicon be in the groove of active area is covered by silicon nitride, makes to be in cut-off region and the region of the groove be connected with the groove of active area and groove both sides is covered by silicon nitride layer;
(11) carry out thermal oxidation, be not oxidized to silicon dioxide by the Polysilicon layer portions that silicon nitride is protected, and be communicated with to merge with the second silicon dioxide layer with the first silicon dioxide layer and form separator, polysilicon layer in active area is closed in the isolation layer, and the polysilicon layer in cut-off region is isolated layer and silicon nitride layer is closed jointly;
(12) adopt photoetching and dry etching successively, form through hole, expose polysilicon layer in the silicon nitride layer of cut-off region;
(13) adopt isotropism gas phase etching, remove polysilicon layer via through hole, form gap;
(14) adopt photoetching and dry etching successively, the silicon nitride layer in selective removal active area and the part of silica of separator, and the end face of the N-type epitaxy layer between the end face of the conductive polycrystalline silicon in groove and adjacent trenches is come out;
(15), in the top layer deposition schottky barrier metal layer of whole mechanism, the through hole in the silicon nitride layer of cut-off region is clogged by Schottky barrier metal, and gap becomes vacuum gap;
(16) are in the surface deposition anode metal layer of total;
(17) adopt the method for bottom surface of grinding monocrystalline substrate to carry out substrate thinning process, and at the bottom surface deposition cathode metal layer of monocrystalline substrate, obtain trench schottky barrier diode.
As preferably, after step (five) technology, repeat step (four) and step (five) 2-9 time, then continue step (six) and complete whole process, manufacture 1-9 vacuum gap in the isolation layer again.
Vacuum gap is provided with in separator of the present invention, because vacuum has relative dielectric constant minimum in known substance, in foundation material, the product of electric field strength and material relative dielectric constant is in different material junctional interfaces place continuous print theorem, the present invention compared with prior art, have higher electric field strength in separator, separator has shared larger reverse bias voltage; For silicon dioxide as insolated layer materials, silicon dioxide relative dielectric constant is 3.9, the relative dielectric constant of the N-type epitaxy layer that monocrystalline silicon obtains is 11.9, vacuum relative dielectric constant is 1, suppose that separator 1/3rd thickness of the present invention is vacuum gap, 2/3rds thickness are silicon dioxide, and the simple silicon dioxide separator of thickness same as the prior art compares, and the electric field strength in separator of the present invention is the twice of prior art silicon dioxide separator.And the area that the distribution curve of electric field strength relative thickness surrounds is voltage.Therefore, device of the present invention can realize higher reverse BV; And under same reverse bias condition, the separator of device of the present invention has shared higher reverse biased, the reverse biased born needed for N-type epitaxy layer and Schottky barrier has significantly reduced, thus reduces device reverse leakage, improves the reliability of device.The reverse biased born because of Schottky barrier is low, the schottky barrier metal layer that potential barrier is lower then can be used to open pressure drop to reduce device forward, greatly improve device forward conduction characteristic, and in general, contained by the lower metal of potential barrier, precious metal ratios is low, therefore schottky barrier metal layer cost is low, can reduce the cost of whole device.
Therefore, the present invention has following beneficial effect:
(1) be provided with vacuum gap in separator, separator has shared higher electric field strength;
(2) separator has shared higher electric field strength, and the Schottky barrier diode in the present invention has higher reverse BV;
(3) under same reverse bias condition, separator in Schottky barrier diode of the present invention has shared higher reverse biased, the reverse biased born needed for epitaxial loayer and Schottky barrier significantly reduces, thus reduce diode reverse electric leakage, improve the reliability of Schottky barrier diode in the present invention.
(4) reverse biased born of Schottky barrier is low, the schottky barrier metal layer that potential barrier is lower can be used to open pressure drop to reduce diode forward, greatly can improve device forward conduction characteristic, and precious metal ratios is low contained by the lower metal level of potential barrier, therefore schottky barrier metal layer cost is low, can reduce the cost of whole Schottky barrier diode.
Accompanying drawing explanation
Fig. 1 is a kind of profile of trench schottky barrier diode embodiment 1 of the present invention;
Fig. 2 ~ Fig. 6 is the step schematic diagram of the manufacture method embodiment 1 of trench schottky barrier diode of the present invention, and wherein (a) is device active region, and (b) is device cut-off region;
Fig. 7 is the schematic diagram of the manufacture method embodiment 4 of trench schottky barrier diode of the present invention, and wherein (a) is device active region, and (b) is device cut-off region;
In figure: anode metal layer 1, schottky barrier metal layer 2, N-type epitaxy layer 3, substrate 4, cathode metal layer 5, groove 6, conductive polycrystalline silicon 7, separator 8, vacuum gap 9, first silicon dioxide layer 10, polysilicon layer 11, the second silicon dioxide layer 12, silicon nitride layer 13, through hole 14, gap 15, the second vacuum gap 16.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.
Method in following embodiment, if no special instructions, is this area conventional method.
Embodiment 1
As shown in Figure 1, a kind of trench schottky barrier diode, comprise the active area at middle part and be surrounded with the cut-off region in source region, active area is made up of anode metal layer 1, schottky barrier metal layer 2, the first conduction type lightly doped N-type heavily doped monocrystalline substrate 4 of N-type epitaxy layer 3, first conduction type and cathode metal layer 5 from top to bottom successively; N-type epitaxy layer top is provided with some grooves 6, and groove 6 is horizontally arranged at interval; The end face of the N-type epitaxy layer 3 between schottky barrier metal layer 2 and adjacent trenches forms Schottky Barrier Contact; Be filled with conductive polycrystalline silicon 7 in groove 6, end face and the schottky barrier metal layer 2 of conductive polycrystalline silicon 7 form ohmic contact; Be provided with separator 8 between conductive polycrystalline silicon 7 and groove 6, the inside of separator 8 is provided with vacuum gap 9; Groove 6 is interconnected in active area and cut-off region.Wherein, separator 8 is silicon dioxide layer, and the width of vacuum gap 9 is 10, and the vacuum degree of vacuum gap 9 is 1 holder, and the thickness of schottky barrier metal layer 2 is 10.
Trench schottky barrier diode manufacture method of the present invention, comprises the following steps:
(1) in the heavily doped monocrystalline substrate of the first conduction type 4, the lightly doped N-type epitaxy layer 3 of first kind conduction type is grown;
(2) adopt photoetching successively and be dry-etched in N-type epitaxy layer 3 and etch groove 6;
(3) in the top layer growth regulation one silica layer 10 of total;
(4) at the top layer growing polycrystalline silicon layer 11 of total;
(5) the second silicon dioxide layer 12 is grown at the top layer of total;
(6) at the top layer deposition conductive polycrystalline silicon 7 of total, conductive polycrystalline silicon is full of groove 6;
(7) adopt dry etching selective removal partially conductive polysilicon, make the end face of conductive polycrystalline silicon 7 flush (see figure 2) with the end face of N-type epitaxy layer 3;
(8) adopt dry etching selective removal part second silicon dioxide layer, the polysilicon layer 11 making to be on the top of N-type epitaxy layer 3 between adjacent trenches exposes to the open air out;
(9) at the top layer deposition silicon nitride layer 13 of total;
(10) photoetching and dry etching is adopted to remove not by silicon nitride layer that photoresist is protected successively, the top layer of the conductive polycrystalline silicon 7 be in the groove 6 of active area is covered by silicon nitride, makes to be in cut-off region and the region of the groove 6 be connected with the groove of active area and groove both sides is covered (see figure 3) by silicon nitride layer 13;
(11) carry out thermal oxidation, polysilicon layer 11 partial oxidation do not protected by silicon nitride is silicon dioxide, and be communicated with to merge with the second silicon dioxide layer 12 with the first silicon dioxide layer 10 and form separator 8, polysilicon layer 11 in active area is closed in separator 8, and the polysilicon layer 11 in cut-off region is isolated layer 8 and silicon nitride layer 13 is closed jointly;
(12) adopt photoetching and dry etching successively, in the silicon nitride layer 12 of cut-off region, form through hole 14, expose polysilicon layer 11(and see Fig. 4);
(13) adopt isotropism gas phase etching, remove polysilicon layer 11 via through hole 14, form gap 15;
(14) adopt photoetching and dry etching successively, silicon nitride layer 13 in selective removal active area and the part of silica of separator 8, make the end face of the N-type epitaxy layer 3 between the end face of the conductive polycrystalline silicon 7 in groove 6 and adjacent trenches come out (see figure 5);
(15), in the top layer deposition schottky barrier metal layer 2 of whole mechanism, the through hole 14 in the silicon nitride layer of cut-off region is clogged by Schottky barrier metal, and gap 15 becomes vacuum gap 9;
(16) are in the surface deposition anode metal layer 1 of total;
(17) adopt the method for bottom surface of grinding monocrystalline substrate 4 to carry out substrate thinning process, and at the bottom surface deposition cathode metal layer 5 of monocrystalline substrate 4, obtain trench schottky barrier diode (see figure 6).
Embodiment 2
The structure of the present embodiment trench schottky barrier diode is identical with embodiment 1, and difference is, in the present embodiment, the width of vacuum gap 9 is 200, and the vacuum degree of vacuum gap 9 is 10
-3holder, the thickness of schottky barrier metal layer 2 is 1000;
The manufacture method of the present embodiment trench schottky barrier diode is in the same manner as in Example 1.
Embodiment 3
The structure of the present embodiment trench schottky barrier diode is identical with embodiment 1, and difference is, in the present embodiment, the width of vacuum gap 9 is 1000, and the vacuum degree of vacuum gap 9 is 10
-6holder, the thickness of schottky barrier metal layer 2 is 5000;
The manufacture method of the present embodiment trench schottky barrier diode is in the same manner as in Example 1.
Embodiment 4
The structure of the present embodiment trench schottky barrier diode is roughly the same with embodiment 1, and difference is, except vacuum gap 9 is also provided with the second vacuum gap 16;
The manufacture method of the present embodiment trench schottky barrier diode has embodiment 1 roughly the same, difference is, the present embodiment is after the Making programme step (five) of embodiment 1 completes, repeat step (four) and step (five) 1 times again, then continue step (six) and complete whole flow process, the second vacuum gap 16(can be produced in the isolation layer and see Fig. 7).
Embodiment 5
The structure of the present embodiment trench schottky barrier diode is roughly the same with embodiment 1, and difference is, is provided with 6 vacuum gaps;
The manufacture method of the present embodiment trench schottky barrier diode has embodiment 1 roughly the same, difference is, the present embodiment is after the Making programme step (five) of embodiment 1 completes, repeat step (four) and step (five) 5 times again, then continue step (six) and complete whole flow process, 5 vacuum gaps can be produced in the isolation layer again, make in structure, there are 6 vacuum gaps.
Embodiment 6
The structure of the present embodiment trench schottky barrier diode is roughly the same with embodiment 1, and difference is, is provided with 10 vacuum gaps;
The manufacture method of the present embodiment trench schottky barrier diode has embodiment 1 roughly the same, difference is, the present embodiment is after the Making programme step (five) of embodiment 1 completes, repeat step (four) and step (five) 9 times again, then continue step (six) and complete whole flow process, 9 vacuum gaps can be produced in the isolation layer again, make in structure, there are 10 vacuum gaps.
Claims (8)
1. a trench schottky barrier diode, it is characterized in that: comprise the active area at middle part and be surrounded with the cut-off region in source region, active area is made up of anode metal layer (1), schottky barrier metal layer (2), the lightly doped N-type epitaxy layer of the first conduction type (3), the heavily doped monocrystalline substrate of the first conduction type (4) and cathode metal layer (5) from top to bottom successively; N-type epitaxy layer top is provided with some grooves (6), and groove (6) is horizontally arranged at interval; The end face of the N-type epitaxy layer (3) between schottky barrier metal layer (2) and adjacent trenches forms Schottky Barrier Contact; Be filled with conductive polycrystalline silicon (7) in groove (6), end face and the schottky barrier metal layer (2) of conductive polycrystalline silicon (7) form ohmic contact; Be provided with separator (8) between conductive polycrystalline silicon (7) and groove (6), the inside of separator (8) is provided with vacuum gap (9); Groove (6) is interconnected in active area and cut-off region.
2. a kind of trench schottky barrier diode according to claim 1, is characterized in that: described separator (8) is silicon dioxide layer.
3. a kind of trench schottky barrier diode according to claim 1, is characterized in that: the width of described vacuum gap (9) is 10 ~ 1000.
4. a kind of trench schottky barrier diode according to claim 1 or 3, is characterized in that: the vacuum degree of described vacuum gap (9) is 1 ~ 10
-6holder.
5. a kind of trench schottky barrier diode according to claim 1 or 3, is characterized in that: described vacuum gap (9) has 1 ~ 10.
6. a kind of trench schottky barrier diode according to claim 1, is characterized in that: the thickness of described schottky barrier metal layer (2) is 10 ~ 5000.
7. a manufacture method for Schottky barrier diode according to claim 1, is characterized in that comprising the following steps:
(1) at the heavily doped monocrystalline substrate of the first conduction type (4) the upper growth lightly doped N-type epitaxy layer of first kind conduction type (3);
(2) adopt photoetching successively and be dry-etched in N-type epitaxy layer (3) and etch groove (6);
(3) in the top layer growth regulation one silica layer (10) of total;
(4) at the top layer growing polycrystalline silicon layer (11) of total;
(5) the second silicon dioxide layer (12) is grown at the top layer of total;
(6) at the top layer deposition conductive polycrystalline silicon (7) of total, conductive polycrystalline silicon is full of groove (6);
(7) adopt dry etching selective removal partially conductive polysilicon, the end face of conductive polycrystalline silicon (7) is flushed with the end face of N-type epitaxy layer (3);
(8) adopt dry etching selective removal part second silicon dioxide layer, the polysilicon layer (11) making to be on the top of N-type epitaxy layer between adjacent trenches (3) exposes to the open air out;
(9) at the top layer deposition silicon nitride layer (13) of total;
(10) photoetching and dry etching is adopted to remove not by silicon nitride layer that photoresist is protected successively, the top layer of the conductive polycrystalline silicon (7) be in the groove (6) of active area is covered by silicon nitride, makes to be in cut-off region and the region of the groove (6) be connected with the groove of active area and groove both sides is covered by silicon nitride layer (13);
(11) carry out thermal oxidation, polysilicon layer (11) partial oxidation do not protected by silicon nitride is silicon dioxide, and be communicated with to merge with the second silicon dioxide layer (12) with the first silicon dioxide layer (10) and form separator (8), polysilicon layer (11) in active area is closed in separator (8), and the polysilicon layer (11) in cut-off region is isolated layer (8) and silicon nitride layer (13) is closed jointly;
(12) adopt photoetching and dry etching successively, form through hole (14), expose polysilicon layer (11) in the silicon nitride layer (12) in cut-off region;
(13) adopt isotropism gas phase etching, remove polysilicon layer (11) via through hole (14), form gap (15);
(14) adopt photoetching and dry etching successively, silicon nitride layer (13) in selective removal active area and the part of silica of separator (8), make the end face of the N-type epitaxy layer (3) between the end face of the conductive polycrystalline silicon (7) in groove (6) and adjacent trenches come out;
(15), in the top layer deposition schottky barrier metal layer (2) of whole mechanism, the through hole (14) in the silicon nitride layer of cut-off region is clogged by Schottky barrier metal, and gap (15) become vacuum gap (9);
(16) are in the surface deposition anode metal layer (1) of total;
(17) adopt the method for bottom surface of grinding monocrystalline substrate (4) to carry out substrate thinning process, and at the bottom surface deposition cathode metal layer (5) of monocrystalline substrate (4), obtain trench schottky barrier diode.
8. the manufacture method of a kind of Schottky barrier diode according to claim 7, it is characterized in that: after step (five) technology, repeat step (four) and step (five) 1-9 time, then continue step (six) and complete whole process, in separator (8), manufacture 1-9 vacuum gap (9) again.
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| CN107369720A (en) * | 2017-07-05 | 2017-11-21 | 西安交通大学 | A kind of p-type diamond height barrier Schottky diode and preparation method thereof |
| CN108155097A (en) * | 2017-12-15 | 2018-06-12 | 中国电子科技集团公司第四十七研究所 | The production method of polycrystalline silicon Schotty diode |
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| US20050062124A1 (en) * | 2003-09-08 | 2005-03-24 | Davide Chiola | Thick field oxide termination for trench schottky device and process for manufacture |
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