CN209216985U - High voltage Schottky diode - Google Patents
High voltage Schottky diode Download PDFInfo
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- CN209216985U CN209216985U CN201920129725.9U CN201920129725U CN209216985U CN 209216985 U CN209216985 U CN 209216985U CN 201920129725 U CN201920129725 U CN 201920129725U CN 209216985 U CN209216985 U CN 209216985U
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Abstract
The utility model relates to a kind of high voltage Schottky diodes, it includes P type substrate, n type buried layer, N-type deep trap, the first N-type well region, p-type protection ring, P type trap zone, the first N-type region, cathode potential layer, the second N-type well region, the second N-type region, anode potential layer, p type island region, substrate electric potential layer, separation layer, polysilicon field plate, protective layer, cathode potential extraction pole, anode potential extraction pole, substrate electric potential extraction pole, cathode potential connects pole, anode potential connects pole and connect pole with substrate electric potential.The utility model increases the radius of curvature of edge depletion layer, so that edge surface electric field be made to be obviously reduced, reduces leakage current, improves voltage endurance capability.The utility model can reduce the electric field strength on surface with shielded surfaces electric field, reduce reverse current, to improve breakdown reverse voltage.
Description
Technical field
The utility model belongs to technical field of semiconductor device, is related to a kind of high voltage Schottky diode.
Background technique
Schottky diode (Schottky Barrier Diode, be abbreviated as SBD) is to utilize metal and semiconductor contact
The metal-semiconductor junction principle production of formation.Therefore, SBD is also referred to as metal-semiconductor (contact) diode or surface
Barrier diode, it is a kind of hot carrier diode.
Schottky diode is that noble metal (gold, silver, aluminium, platinum etc.) A is anode, using N-type semiconductor B as cathode, utilizes two
The potential barrier formed on person's contact surface manufactured metal-semiconductor device with rectification characteristic.Because in N-type semiconductor there is
A large amount of electronics, only minimal amount of free electron in noble metal, so electronics is just from A low to concentration in highly concentrated B
Diffusion.Obviously, there is no hole in metal A, diffusion motion of the hole from A to B is also just not present.As electronics is constantly spread from B
To A, B surface electron concentration is gradually decreased, and surface electroneutrality is destroyed, and then just forms potential barrier, and direction of an electric field is B → A.But
Under the electric field action, the electronics in A can also generate the drift motion from A → B, to slacken due to diffusion motion and shape
At electric field.After setting up the space-charge region of one fixed width, electronics drift motion caused by electric field and concentration difference cause
Electrons spread movement reach opposite balance, just form Schottky barrier.
Schottky diode is made using the metal-semiconductor junction principle that metal and semiconductor contact are formed, cut-in voltage
It is smaller.Due to being monopole current-carrying subconductivity, Schottky diode does not have superfluous minority carrier accumulation in forward conduction, because
This Reverse recovery is very fast.But Schottky diode reverse leakage is bigger, temperature characterisitic is poor.Further, since Schottky two
Pole pipe is single carrier conductive devices, there is " the silicon limit " between breakdown voltage and forward conduction resistance.It improves
The breakdown voltage of Schottky diode needs to increase drift region thickness and/or reduces drift doping concentration and still in this way must
The increase for so leading to raising and the forward conduction loss of the forward conduction voltage drop of Schottky diode, to limit Schottky
Application of the diode in high pressure field.
Summary of the invention
The purpose of the utility model is to overcome the deficiencies in the prior art, provide a kind of high pressure resistant, reverse leakage current
Small high voltage Schottky diode.
According to technical solution provided by the utility model, the high voltage Schottky diode, in the upper surface of P type substrate
Embedded with n type buried layer, it is equipped with N-type deep trap in the upper surface of P type substrate and n type buried layer, is embedded with first in the upper surface of N-type deep trap
N-type well region, p-type protection ring and P type trap zone are embedded with the first N-type region in the upper surface of the first N-type well region, in the first N-type well region
It is equipped with cathode potential layer with the upper surface of the first N-type region, the second N-type well region is equipped in p-type protection ring, in the second N-type well region
Upper surface be embedded with the second N-type region, anode potential layer is equipped in the upper surface of the second N-type well region and the second N-type region, in p-type
The upper surface of well region is embedded with p type island region, P type trap zone and p type island region upper surface be equipped with substrate electric potential layer, the first N-type well region,
The upper surface of N-type deep trap on the outside of p-type protection ring and P type trap zone is equipped with separation layer, and separation layer and p-type protection ring pass through polysilicon
Field plate is connected, and protective layer is equipped on separation layer, is equipped with cathode potential extraction pole, anode potential extraction in the upper surface of protective layer
Pole and substrate electric potential extraction pole, cathode potential extraction pole connect pole phase by the cathode potential in protective layer with cathode potential layer
Even, anode potential extraction pole is connect by the anode potential in protective layer with anode potential layer and is extremely connected, substrate electric potential extraction pole
It is connect with substrate electric potential layer by the substrate electric potential in protective layer and is extremely connected；In the height direction, the upper table of the first N-type well region
The upper surface in face, the upper surface of p-type protection ring and P type trap zone is respectively positioned on the top of the upper surface of N-type deep trap, the first N-type well region
Upper surface be located between the upper surface and lower surface of separation layer, the upper surface of P type trap zone is located at the upper surface of separation layer under
Between surface, the upper surface of p-type protection ring is located between the upper surface and lower surface of separation layer.
As preferred: the polysilicon field plate covering part p-type protection ring, and polysilicon field plate width is p-type protection ring
The 1/4 ~ 3/4 of width.
As preferred: first N-type region is located at the top of n type buried layer.
As preferred: in the height direction, the upper surface of p-type protection ring is concordant with the upper surface of the second N-type well region.
Utility model has the advantages that
1, due to the p-type protection ring of the second N-type well region, the radius of curvature of edge depletion layer is increased, to make edge table
Face electric field is obviously reduced, and reduces leakage current, improves voltage endurance capability.
2, since N trap increases the N of heavy doping+Well region, p-well increase the P of heavy doping+Well region, can be with shielded surfaces electric field, i.e.,
The electric field strength on surface is reduced, reduces reverse current, to improve breakdown reverse voltage.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the utility model.
Specific embodiment
The utility model is described in further detail combined with specific embodiments below.
The high voltage Schottky diode of the utility model is embedded with n type buried layer 2 in the upper surface of P type substrate 1, serves as a contrast in p-type
Bottom 1 and the upper surface of n type buried layer 2 are equipped with N-type deep trap 3, are embedded with the first N-type well region 4, p-type guarantor in the upper surface of N-type deep trap 3
Retaining ring 8 and P type trap zone 6, are embedded with the first N-type region 7 in the upper surface of the first N-type well region 4, in the first N-type well region 4 and the first N
The upper surface in type area 7 is equipped with cathode potential floor 15, the second N-type well region 5 is equipped in p-type protection ring 8, in the second N-type well region 5
Upper surface is embedded with the second N-type region 9, anode potential layer 16 is equipped in the upper surface of the second N-type well region 5 and the second N-type region 9, in P
The upper surface of type well region 6 is embedded with p type island region 11, substrate electric potential layer 17 is equipped in the upper surface of P type trap zone 6 Yu p type island region 11, the
The upper surface of the N-type deep trap 3 in 6 outside of one N-type well region 4, p-type protection ring 8 and P type trap zone is equipped with separation layer 10, separation layer 10 and P
Type protection ring 8 is connected by polysilicon field plate 18, and protective layer 22 is equipped on separation layer 10, is equipped in the upper surface of protective layer 22
Cathode potential extraction pole 12, anode potential extraction pole 13 and substrate electric potential extraction pole 14, cathode potential extraction pole 12 and cathode electricity
Position layer 15 connects pole 19 by the cathode potential in protective layer 22 and is connected, and anode potential extraction pole 13 passes through with anode potential layer 16
Anode potential connection pole 20 in protective layer 22 is connected, and substrate electric potential extraction pole 14 and substrate electric potential layer 17 pass through in protective layer 22
Substrate electric potential connection pole 21 be connected；In the height direction, the upper surface of the first N-type well region 4, p-type protection ring 8 upper surface with
The upper surface of P type trap zone 6 is respectively positioned on the top of the upper surface of N-type deep trap 3, and the upper surface of the first N-type well region 4 is located at separation layer 10
Upper surface and lower surface between, the upper surface of P type trap zone 6 is located between the upper surface and lower surface of separation layer 10, p-type protection
The upper surface of ring 8 is located between the upper surface and lower surface of separation layer 10.
The 18 covering part p-type protection ring 8 of polysilicon field plate, and 18 width of polysilicon field plate is 8 width of p-type protection ring
1/4 ~ 3/4.
First N-type region 7 is located at the top of n type buried layer 2.
In the height direction, the upper surface of p-type protection ring 8 is concordant with the upper surface of the second N-type well region 5.
The utility model increases the radius of curvature of edge depletion layer, to make edge due to being provided with p-type protection ring 8
Surface field is obviously reduced, and reduces leakage current, improves voltage endurance capability.
The utility model is due to being provided with separation layer 10, anode and cathode is isolated, occurs short circuit when circuit being avoided to work
Or conductive abnormal conditions.
The utility model is equipped with second due to being equipped with the first N-type region 7 in the first N-type well region 4 in the second N-type well region 5
N-type region 9 can reduce the electric field strength on surface with shielded surfaces electric field, reduce reverse current, to improve reverse breakdown electricity
Pressure.
In order to improve the voltage endurance capability of Schottky diode, the first N-type well region 4 and the second N-type well region 5 are all that N is lightly doped
Type area, the first N-type region 7 and the second N-type region 9 are all heavily doped N-type areas.
In order to reduce Ohmic contact, p type island region 11 is heavy doping.
Above-mentioned high voltage Schottky diode can be implemented using following process:
Step 1 forms n type buried layer 2 in P type substrate 1, and forming method is ion implanting, is then promoted；
Step 2, ion implanting and propulsion form N-type deep trap 3；
Step 3, the first N-type well region 4, the second N-type well region 5 carry out ion in same time utilization P or other pentads
Injection；
Step 4 forms separation layer 10 on 3 surface of N-type deep trap；
Step 5, use B or other triads carry out ion implanting formed the p-type protection ring 8 that the 2nd N well region surrounds with
And the P type trap zone 6 below substrate electric potential draw-out area；
Step 6 forms the first N-type region 7 and the second N-type region 9, the first N-type region using photoetching process and P ion injection technology
7 are used as cathode draw-out area, and the second N-type region 9 is used as anode draw-out area, recycle photoetching process and B ion implantation technology shape later
At p type island region 11, p type island region 11 is used as substrate electric potential draw-out area, and the first N-type region 7, the second N-type region 9 and p type island region 11 are heavy doping
Area；
Step 7, depositing polysilicon simultaneously return quarter, form polysilicon field plate 18；
Step 8 forms metal layer using techniques such as sputterings, carries out lithography and etching later, remove extra metal layer, shape
At cathode potential extraction pole 12, cathode potential connection pole 19, anode potential extraction pole 13, anode potential connection pole 20, substrate electricity
Position extraction pole 14 connect pole 21 with substrate electric potential, completes to cathode potential layer 15, anode potential layer 16 and substrate electric potential layer 17
It draws.
The utility model increases the p-type protection ring of the second N-type well region, increases the radius of curvature of edge depletion layer, from
And it is obviously reduced edge surface electric field, leakage current is reduced, voltage endurance capability is improved.And increase the N of heavy doping in N trap+Well region,
The P of p-well increase heavy doping+Well region can reduce the electric field strength on surface with shielded surfaces electric field, reduce reverse current, thus
Improve breakdown reverse voltage.
Claims (4)
1. a kind of high voltage Schottky diode, it is characterized in that: n type buried layer (2) are embedded in the upper surface of P type substrate (1), in P
The upper surface of type substrate (1) and n type buried layer (2) is equipped with N-type deep trap (3), is embedded with the first N-type in the upper surface of N-type deep trap (3)
Well region (4), p-type protection ring (8) and P type trap zone (6), are embedded with the first N-type region (7) in the upper surface of the first N-type well region (4),
Cathode potential layer (15) are equipped in the upper surface of the first N-type well region (4) and the first N-type region (7), are equipped in p-type protection ring (8)
Second N-type well region (5) is embedded with the second N-type region (9) in the upper surface of the second N-type well region (5), the second N-type well region (5) with
The upper surface of second N-type region (9) is equipped with anode potential layer (16), is embedded with p type island region (11) in the upper surface of P type trap zone (6),
The upper surface of P type trap zone (6) and p type island region (11) is equipped with substrate electric potential layer (17), in the first N-type well region (4), p-type protection ring (8)
Separation layer (10) are equipped with the upper surface of the N-type deep trap (3) on the outside of P type trap zone (6), separation layer (10) and p-type protection ring (8) are logical
It crosses polysilicon field plate (18) to be connected, is equipped with protective layer (22) on separation layer (10), be equipped with yin in the upper surface of protective layer (22)
Electrode potential extraction pole (12), anode potential extraction pole (13) and substrate electric potential extraction pole (14), cathode potential extraction pole (12) with
Cathode potential layer (15) is connected by cathode potential connection pole (19) in protective layer (22), anode potential extraction pole (13) and sun
Electrode potential layer (16) is connected by anode potential connection pole (20) in protective layer (22), substrate electric potential extraction pole (14) and substrate
Equipotential layer (17) is connected by substrate electric potential connection pole (21) in protective layer (22)；In the height direction, the first N-type well region
(4) the upper surface of upper surface, p-type protection ring (8) and the upper surface of P type trap zone (6) is respectively positioned on the upper surface of N-type deep trap (3)
Top, the upper surface of the first N-type well region (4) is located between the upper surface and lower surface of separation layer (10), P type trap zone (6)
Upper surface is located between the upper surface and lower surface of separation layer (10), and the upper surface of p-type protection ring (8) is located at separation layer (10)
Between upper surface and lower surface.
2. high voltage Schottky diode as described in claim 1, it is characterized in that: the polysilicon field plate (18) covering part P
Type protection ring (8), and polysilicon field plate (18) width is the 1/4 ~ 3/4 of p-type protection ring (8) width.
3. high voltage Schottky diode as described in claim 1, it is characterized in that: first N-type region (7) is located at n type buried layer
(2) top.
4. high voltage Schottky diode as described in claim 1, it is characterized in that: in the height direction, p-type protection ring (8)
Upper surface is concordant with the upper surface of the second N-type well region (5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920129725.9U CN209216985U (en) | 2019-01-25 | 2019-01-25 | High voltage Schottky diode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920129725.9U CN209216985U (en) | 2019-01-25 | 2019-01-25 | High voltage Schottky diode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209216985U true CN209216985U (en) | 2019-08-06 |
Family
ID=67467604
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920129725.9U Active CN209216985U (en) | 2019-01-25 | 2019-01-25 | High voltage Schottky diode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209216985U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113363273A (en) * | 2021-05-31 | 2021-09-07 | 武汉新芯集成电路制造有限公司 | Photosensitive array and imaging device |
| CN114709254A (en) * | 2022-04-01 | 2022-07-05 | 无锡友达电子有限公司 | High-voltage parallel diode structure with composite buried layer and preparation method thereof |
-
2019
- 2019-01-25 CN CN201920129725.9U patent/CN209216985U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113363273A (en) * | 2021-05-31 | 2021-09-07 | 武汉新芯集成电路制造有限公司 | Photosensitive array and imaging device |
| CN113363273B (en) * | 2021-05-31 | 2023-11-24 | 武汉新芯集成电路制造有限公司 | Photosensitive array and imaging device |
| CN114709254A (en) * | 2022-04-01 | 2022-07-05 | 无锡友达电子有限公司 | High-voltage parallel diode structure with composite buried layer and preparation method thereof |
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