CN102347373A - Schottky diode - Google Patents
Schottky diode Download PDFInfo
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- CN102347373A CN102347373A CN2010102460938A CN201010246093A CN102347373A CN 102347373 A CN102347373 A CN 102347373A CN 2010102460938 A CN2010102460938 A CN 2010102460938A CN 201010246093 A CN201010246093 A CN 201010246093A CN 102347373 A CN102347373 A CN 102347373A
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- schottky diode
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Abstract
The invention discloses a Schottky diode which comprises an ohm layer, a metal layer and a drifting channel, wherein the ohm layer is used as a cathode; the metal layer is used as an anode; the drifting channel is formed by semi-conductor materials and extends between the ohm layer and the metal layer; and the drifting channel comprises a heavy doped region adjacent ohm contact layer. According to the invention, the drifting channel and the metal layer form a Schottky barrier; and when a Schottky diode has reverse bias, a clamping mechanism is used for clamping the drifting channel. Thus, the saturated or leakage current degree between the metal layer and the ohm contact layer is reduced under the condition of the reverse bias of the Schottky diode.
Description
Technical field
The invention relates to a kind of electronic component, and, be applicable to as rectifier cell particularly relevant for a kind of semiconductor element.
Background technology
Schottky diode (Schottky diodes) has used for many years on semi-conductor industry, for example, is used as clamper and rectifier.Schottky diode is the diode that comprises the metal-semiconductor interface, and wherein the metal-semiconductor interface is to form a Schottky barrier (Schottky barrier).This metal-semiconductor interface generally includes metal level and is connected to doping semiconductor layer.Schottky barrier is formed at the knot of this metal level and this doping semiconductor layer.
For being in forward bias voltage drop and the metal-semiconductor interface that is in reverse bias, its barrier height has very big difference.When applying enough forward bias voltage drop, this potential barrier is removed basically, allows electronics freely to flow to metal from semi-conducting material by this.
Because the forward drop of Schottky diode is less than the forward drop of PN junction diode, Schottky diode provides efficient rectification in power application.Moreover these elements have instantaneous recovery time, make them be specially adapted to high-frequency rectification.
Well known, Schottky diode often has not good converse electrical leakage characteristic.In order to improve this electric leakage characteristic, the means that increase protective ring to the Schottky diode structure of an opposite polarity carrier exist.Yet making this protective ring needs the additional mask step usually.And protective ring occupies the space, makes the Schottky diode with protective ring need more multilist space of planes compared to the Schottky diode that does not have protective ring like this.
Therefore, need seek alternative method in order to improve the converse electrical leakage characteristic of Schottky diode.
Summary of the invention
Compared to the Schottky diode of prior art, comprise a plurality of embodiment in the Schottky diode of this exposure method relevant with Schottky diode, it has the converse electrical leakage of attenuating.
According to some aspects of this exposure, a kind of Schottky diode can comprise an ohmic contact layer, a metal level and a drift passage, and the drift passage extends between ohmic contact layer and the metal level.Folder ends mechanism in order at Schottky diode folder passage that only drifts about during by reverse bias.
Folder ends mechanism can comprise one first trap and a control gate.Folder ends mechanism can more comprise one second trap, and wherein first and second traps can be positioned at the relative both sides of drift passage.First and second traps are that the semi-conducting material by first conductivity type forms, and the drift passage is that the semi-conducting material by second conductivity type forms.First conductivity type can for example be P-type conduction property, and second conductivity type can for example be a N type conductivity.
Control gate is extensible between first and second traps, and passes through the drift passage.Control gate can comprise a dielectric layer and a conductor layer.Conductor layer can be formed by polysilicon, and dielectric layer can be formed by silicon dioxide.
The drift passage can be formed in one first substrate, and this first substrate has a contact-making surface, and wherein first substrate is that semi-conducting material by first conductivity type forms.First substrate can be formed in the trap of one second substrate, and wherein second substrate is that semi-conducting material by second conductivity type forms.
Control gate can be electrically connected to metal level.
The drift passage can comprise a light dope part contiguous metal layer relatively, and a heavy doping relatively part is in abutting connection with ohmic contact layer.
Schottky diode can comprise only mechanism of first and second folders, and in certain embodiments, when the Schottky diode reverse bias, first and second folders end mechanism and can only press from both sides for each branch of drift passage.
According to some aspects of this exposure, a kind of Schottky diode can comprise a Schottky barrier, a drift passage, semi-conductive substrate and a control gate.The drift passage extends from Schottky barrier.Semiconductor substrate comprises one first substrate part, one second substrate part, and one the 3rd substrate part.Control gate extends between the second and the 3rd substrate part.The second and the 3rd substrate partly is configured at least according to the polarity that is applied to the voltage of control gate, optionally the drift passage is carried out folder and ends condition.
For there is better understanding above-mentioned and other aspect of the present invention, hereinafter specially lift preferred embodiment, and cooperate appended graphicly, elaborate as follows.
Description of drawings
Characteristic of the present invention, aspect and embodiment are together with additional graphic the description, wherein:
Fig. 1 illustrates the plane graph according to the Schottky diode of first embodiment of the invention.
Fig. 2 A illustrates as shown in Figure 1 Schottky diode along the cross section view of transversal 2A-2A.
Fig. 2 B illustrates as shown in Figure 1 Schottky diode along the cross section view of transversal 2B-2B.
Fig. 2 C illustrates when the Schottky diode reverse bias as shown in Figure 1 Schottky diode along the cross section view of transversal 2B-2B.
Fig. 3 illustrates the plane graph according to the Schottky diode of second embodiment of the invention.
Fig. 4 A illustrates as shown in Figure 3 Schottky diode along the cross section view of transversal 4A-4A.
Fig. 4 B illustrates as shown in Figure 3 Schottky diode along the cross section view of transversal 4B-4B.
Fig. 5 illustrates the plane graph according to the Schottky diode of third embodiment of the invention.
[main element symbol description]
100,200,300: Schottky diode
102,204: Semiconductor substrate
102a: contact-making surface
102b: the first of substrate 102
102c: the first trap part
102d: the second trap part
102e: triple-well part
102f: the 4th trap part
104: the drift passage
104a: the first of drift passage
104b: the second portion of drift passage
104b ': first branch of drift passage second portion
104b ": second branch of drift passage second portion
104b ' ": the 3rd branch of drift passage second portion
106: ohmic contact layer
107: Schottky barrier
108: metal level
110: anode
112: negative electrode
114: control gate
114a: the first of control gate
114b: the second portion of control gate
114c: the third part of control gate
116: dielectric layer
118: conductor layer
120,120a, 120b, 120c: folder ends mechanism
202: substrate (or trap)
202b: the first of substrate (or trap)
Embodiment
First embodiment
Fig. 1 illustrates the plan view of an embodiment of Schottky diode 100.Fig. 2 A illustrates the cross section view of Schottky diode 100 along transversal 2A-2A, and Fig. 2 B illustrates the cross section view of Schottky diode 100 along transversal 2B-2B.Schottky diode 100 comprises Semiconductor substrate 102, and normally the silicon of first conductivity type (normally P-type conduction property of first conductivity type) has contact-making surface 102a.Drift passage (drift channel) 104 is second conductivity type (a normally N type conductivity), is formed in the 102b of first of substrate 102.The 102b of first of substrate 102 is light dope relatively, and is represented by P-like figure.
Shown in Fig. 2 A, drift path 10 4 extends between ohmic contact layer 106 and the metal level 108.The 104a of first of drift path 10 4 is in abutting connection with ohmic contact layer 106, and normally heavy doping relatively of the 104a of first of drift path 10 4 is represented by N+ like figure.The second portion 104b of drift path 10 4 extends to metal level 108 from the 104a of first.The second portion 104b of drift path 10 4 is light dope relatively, and is represented by N-like figure.
When the semi-conducting material of drift path 10 4 is connected to the metal material of metal level 108, form Schottky barrier 107.When metal was connected with semi-conducting material, the electronics in the N type semiconductor material of drift path 10 4 got started and flows to metal level 108.This electronics flows to cause in the drift path 10 4 and forms a depletion region (depletion region) near the knot place with metal level 108.Depletion region is that drift path 10 4 becomes the zone that sky exhausts main carrier.This electronics flows also to cause in the metal level 108 has a large amount of carriers near the knot place between metal level 108 and the drift path 10 4.Carriers a large amount of in the metal level 108 are being created one negative wall (negative wall) near the knot place between metal level 108 and the drift path 10 4.This " negative position wall " formation face barrier is called as " Schottky barrier " 107.
Schottky diode 100 also can comprise anode electrode 110 and cathode electrode 112, and anode electrode 110 is connected to metal level 108, and cathode electrode 112 is connected to ohmic contact layer 106.Therefore applying a forward bias voltage drop to Schottky diode 100 can comprise the current potential that metal level 108 is applied calibration, and to applying relatively negative current potential on the ohmic contact layer 106.Because the positive potential that applies attracts the electronics from Schottky barrier 107 zones, forward bias voltage drop will reduce the intensity of Schottky barrier 107.The reducing of the intensity of Schottky barrier 107 allows electronics from ohmic contact layer 106, passes through drift path 10 4, flows to metal level 108.
Shown in Fig. 2 B, second and third part 102c and 102d of substrate 102 are also referred to as first and second trap part 102c and the 102d, are formed at the relative both sides of drift path 10 4.The first and second trap part 102c and 102d heavy doping relatively, represented like figure by P+.Control gate (control gate) 114 extends between the first and second trap part 102c and the 102d.The 114a of first of control gate 114 can the overlapping first trap part 102c, and the second portion 114b of control gate 114 can the overlapping second trap part 102d.And third part 114c extends the second portion 104b that passes through drift path 10 4.
Shown in Fig. 2 A, control gate 114 is electrically connected to metal level 108.
Fig. 2 C illustrates when applying negative potential a to control gate 114, and Schottky diode 100 is along the cross section view of transversal 2B-2B.When Schottky diode 100 reverse bias, control gate 114 obtains negative potential, and this negative potential is applied to anode electrode 110 and metal level 108.Shown in Fig. 2 C, can be inclined to electronics compressing with N type drift path 10 4 toward P type substrate 102 at the negative potential of control gate 114, and attract hole from P type substrate 102, comprise main carrier from trap part 102c and 102d.Combination more to a certain degree can take place between electronics and the hole in the size of the back bias voltage of apparent control gate 114 and deciding, and reduces the quantity of the free electron that can be used for conducting electricity in the N type drift path 10 4.Bias voltage is negative more, and the speed of Jie Heing is high more again.Under the reverse bias condition of Schottky diode 100, along with the reduction bias voltage of control gate 114, therefore saturated the or leakage current degree that between metal level 108 and ohmic contact layer 106, causes reduces.Therefore, the back bias voltage of control gate 114 causes being positioned at the vague and general of drift path 10 4 under the control gate 114, and the folder of the path 10 4 that causes by this drifting about ends (pinch-off).Therefore, when Schottky diode 100 reverse bias, through control gate 114 and be used to press from both sides only drift about trap part 102c and the 102d of path 10 4 and form folder and end mechanism 120.
When Schottky diode 100 forward bias voltage drop, control gate 114 obtains positive potential, and this positive potential is applied to anode electrode 110 and metal level 108.Positive potential at control gate 114 can attract the extra electronics (free carrier) from P type substrate 102, and sets up new carrier through the collision that causes between accelerated particle.When the current potential of control gate 114 continues to increase, the quantity of the free electron that can be used for conducting electricity in the N type drift path 10 4 also increases.When Schottky diode 100 forward bias voltage drop, the increase of free electron can strengthen electronics and flows through Schottky diode 100 in this drift path 10 4.Therefore, when Schottky diode 100 forward bias voltage drop, folder ends machine-processed 120 folders that remove drift path 10 4 and ends.
In certain embodiments, can use various isolation structures to be used for isolating the Schottky diode of this exposure and the electronic component of adjacency.For example, in certain embodiments, use existing silicon selective oxidation (LOCOS) technology can produce shallow isolation structure or use shallow trench isolation (STI).Another example is in shown in Fig. 3 and Fig. 4 A, Fig. 4 B.
Second embodiment
Fig. 3 illustrates the plane graph of second embodiment of Schottky diode 200.In the element of Schottky diode 200, indicate similar or be same as the element of Schottky diode 100 with reference to label, will no longer carry out the description of repetition it in this with identical.Fig. 4 A illustrates the cross section view of Schottky diode 200 along transversal 4A-4A, and Fig. 4 B illustrates the cross section view of Schottky diode 200 along transversal 4B-4B.
The operation of Schottky diode 200; Folder ends only the drift about abilities of path 10 4 of mechanism 120 folders when being included in the reverse bias of Schottky diode 200; And folder ends the ability that machine-processed 120 folders that discharge drift path 10s 4 end when the forward bias voltage drop of Schottky diode 200, all with consistent relevant for the description of Schottky diode 100.Main difference is between Schottky diode 200 and the Schottky diode 100, and Schottky diode 200 comprises extra n type material (substrate 204) at least a portion on every side around the 202b of first of P type substrate (or trap) 202.
The n type material of substrate 204 offers the electrical isolation of Schottky diode 200 and the improvement of the electronic component of adjacency.When the n type material of substrate 204 contacted with the P-type material of substrate 202, in the zone of contiguous N type substrate 204 materials and P type substrate 202 storerooms knot, electronics and hole began to combine.This again cohesive process cause the zone of contiguous this knot to lack carrier.In other words, cause a depletion region, result from that the sky of carrier exhausts in these zones in contiguous N type substrate 204 materials and the zone that P type substrate 202 storerooms are tied.This depletion region comprises a cation potential barrier, makes the most carriers in the P-type material of substrate 202 must overcome the cation potential barrier with in the n type material that migrates to substrate 204.For this reason, almost do not have most carriers can migrate to substrate 204 in the P-type material of substrate 202 and become leakage current.Identical reason, almost not having most carriers can migrate to substrate 202 in the n type material of substrate 204 becomes leakage current.Therefore, the isolation structure of Schottky diode 200 can reduce the round leakage current of 200 of Schottky diodes.
The 3rd embodiment
Fig. 5 illustrates the plane graph of the 3rd embodiment of Schottky diode 300.In the element of Schottky diode 300, indicate similar or be same as the element of Schottky diode 100 with reference to label, will no longer carry out the description of repetition it in this with identical.
The associated description of the structure of Schottky diode 300 and operation and Schottky diode 100 is for similar in fact, and its difference is that Schottky diode 300 comprises that more a plurality of folders end machine-processed 120a to 120c.Therefore; Though be not shown in Fig. 5; Schottky diode 300 can comprise anode 110 and negative electrode 112 (with the explanation of Schottky diode 100 and describe identical); Schottky diode 300 comprises that ohmic contact layer 106 is positioned on the 104a of first of drift path 10 4, and Schottky barrier 107 is positioned on the second portion 104b of drift path 10 4 with metal level 108.
Among the embodiment shown in Figure 5, the second portion 104b of drift path 10 4 comprises that three 104b ' of branch, 104b " and 104b ' " extend between anode 110 and negative electrode 112 zones.Each folder ends machine-processed 120a to 120c and comprises that separately control gate 114 is electrically connected to the anode of Schottky diode 300.Folder ends machine-processed 120a and comprises control gate 114, and control gate 114 comprises the 114a of first of control gate, the second portion 114b of control gate and the third part 114c of control gate.The 114a of first of control gate and the first trap part 102c are overlapping, and the second portion 114b of control gate and the second trap part 102d are overlapping, and the third part 114c of control gate extends first 104b ' of branch that passes through drift path 10 4.Folder ends machine-processed 120b and comprises control gate 114, and control gate 114 comprises the 114a of first of control gate, the second portion 114b of control gate and the third part 114c of control gate.The 114a of first of control gate and the second trap part 102d are overlapping, and the second portion 114b and the triple-well part 102e of control gate are overlapping, and the third part 114c of control gate extends second 104b of branch that passes through drift path 10 4 ".Folder ends machine-processed 120c and comprises control gate 114, and control gate 114 comprises the 114a of first of control gate, the second portion 114b of control gate and the third part 114c of control gate.The 114a of first and the triple-well part 102e of control gate are overlapping, and the second portion 114b of control gate and the 4th trap part 102f are overlapping, and the third part 114c of control gate extends the 3rd 104b ' of branch that passes through drift path 10 4 ".
Folder ends machine-processed 120a to 120c folder only drift about each 104b ' of branch of path 10 4, the ability of 104b " and 104b ' " when the reverse bias of Schottky diode 300; And folder ends the ability that the folder of each 104b ' of branch that machine-processed 120a to 120c discharges drift path 10 4,104b " and 104b ' " ends when the forward bias voltage drop of Schottky diode 300, all ends machine-processed 120 consistent with above-mentioned folder.Yet this multiple-branching construction is applicable to the application of high electric current.
Though more than be with three folders end machine-processed 120a to 120c and each 104b ' of branch, 104b " and 104b ' " illustrates, alternative embodiment can comprise that the folder of any amount ends machine-processed 120a to 120c and each 104b ' of branch, 104b " and 104b ' ".Likewise, an embodiment who substitutes can comprise that a plurality of folders end machine-processed 120a to 120c and each 104b ' of branch, 104b " and 104b ' " together with an isolation structure, for example about the exposure of Schottky diode 200.
In sum, though the present invention discloses as above with preferred embodiment, so it is not in order to limit the present invention.Have common knowledge the knowledgeable in the technical field under the present invention, do not breaking away from the spirit and scope of the present invention, when doing various changes and retouching.Therefore, protection scope of the present invention is when looking being as the criterion that the claim scope of enclosing defined.
Claims (10)
1. Schottky diode comprises:
One ohmic contact layer;
One metal level;
One drift passage extends between this ohmic contact layer and this metal level; And
One folder ends mechanism, in order to folder only should the drift passage during by reverse bias at this Schottky diode.
2. Schottky diode according to claim 1, wherein this folder ends mechanism and comprises one first trap and a control gate.
3. Schottky diode according to claim 2, wherein this folder ends mechanism and more comprises one second trap, and wherein this first is positioned at the relative both sides of this drift passage with this second trap.
4. Schottky diode according to claim 3, wherein this first with this second trap be that semi-conducting material by one first conductivity type forms, wherein should the drift passage be that the semi-conducting material by one second conductivity type forms.
5. Schottky diode according to claim 4, wherein this first conductivity type is a P-type conduction property, wherein this second conductivity type is a N type conductivity.
6. Schottky diode according to claim 4, wherein this control gate extend this first and this second trap between, and pass through this drift passage.
7. Schottky diode according to claim 6, wherein this control gate comprises a dielectric layer and a conductor layer.
8. Schottky diode according to claim 7, wherein this conductor layer is to be formed by polysilicon, this dielectric layer is to be formed by silicon dioxide.
9. Schottky diode according to claim 6 wherein should the drift tunnel-shaped be formed in one first substrate, and this substrate has a contact-making surface, and wherein this substrate is that semi-conducting material by this first conductivity type forms.
10. Schottky diode according to claim 9, wherein this first substrate-like is formed in the trap of one second substrate, and wherein this second substrate is that semi-conducting material by this second conductivity type forms.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010246093 CN102347373B (en) | 2010-08-03 | 2010-08-03 | Schottky diode |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010246093 CN102347373B (en) | 2010-08-03 | 2010-08-03 | Schottky diode |
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| CN102347373A true CN102347373A (en) | 2012-02-08 |
| CN102347373B CN102347373B (en) | 2013-04-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112838131A (en) * | 2021-01-08 | 2021-05-25 | 江苏东海半导体科技有限公司 | Schottky diode based on silicon carbide planar MOS structure |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1591908A (en) * | 2003-08-18 | 2005-03-09 | 谢福淵 | Junction barrier schottky device of low forward flow voltage drop and high reverse blocking voltage |
| CN1977389A (en) * | 2004-06-30 | 2007-06-06 | 飞思卡尔半导体公司 | Schottky device and method of forming |
| US20090179297A1 (en) * | 2008-01-16 | 2009-07-16 | Northrop Grumman Systems Corporation | Junction barrier schottky diode with highly-doped channel region and methods |
| US7705415B1 (en) * | 2004-08-12 | 2010-04-27 | Drexel University | Optical and electronic devices based on nano-plasma |
-
2010
- 2010-08-03 CN CN 201010246093 patent/CN102347373B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1591908A (en) * | 2003-08-18 | 2005-03-09 | 谢福淵 | Junction barrier schottky device of low forward flow voltage drop and high reverse blocking voltage |
| CN1977389A (en) * | 2004-06-30 | 2007-06-06 | 飞思卡尔半导体公司 | Schottky device and method of forming |
| US7705415B1 (en) * | 2004-08-12 | 2010-04-27 | Drexel University | Optical and electronic devices based on nano-plasma |
| US20090179297A1 (en) * | 2008-01-16 | 2009-07-16 | Northrop Grumman Systems Corporation | Junction barrier schottky diode with highly-doped channel region and methods |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112838131A (en) * | 2021-01-08 | 2021-05-25 | 江苏东海半导体科技有限公司 | Schottky diode based on silicon carbide planar MOS structure |
| CN112838131B (en) * | 2021-01-08 | 2022-02-11 | 江苏东海半导体科技有限公司 | Schottky diode based on silicon carbide planar MOS structure |
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| CN102347373B (en) | 2013-04-17 |
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