CN203179885U - Trench MOSFET power rectification device - Google Patents
Trench MOSFET power rectification device Download PDFInfo
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- CN203179885U CN203179885U CN 201320071888 CN201320071888U CN203179885U CN 203179885 U CN203179885 U CN 203179885U CN 201320071888 CN201320071888 CN 201320071888 CN 201320071888 U CN201320071888 U CN 201320071888U CN 203179885 U CN203179885 U CN 203179885U
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- groove
- epitaxial loayer
- protection ring
- terminal protection
- area
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Abstract
The utility model provides a trench MOSFET (Metal-Oxide -Semiconductor Field Effect Transistor) power rectification device, wherein an epitaxial layer of the trench MOSFET power rectification device comprises a first region and a second region around the first region, a first trench is arranged at the first region, the second region of the epitaxial layer has at least one terminal protection ring of a second conduction type surrounding the first trench, the terminal protection ring extends from a surface of the epitaxial layer to an inner part of the epitaxial layer, and the position of a bottom of the terminal protection ring is lower than the position of a bottom of the first trench arranged at the first region of the epitaxial layer. According to the trench MOSFET power rectification device of the utility model, the second region of the epitaxial layer surrounds the first region, thus the terminal protection ring around the first trench can surround the bottom of the first trench, thereby avoiding the first trench from bearing risks of high voltage strength.
Description
Technical field
The utility model relates to semiconductor applications, particularly relates to a kind of groove MOSFET power rectifier device and manufacture method thereof.
Background technology
At present, Chang Yong groove MOSFET power rectifier device adopts United States Patent (USP) 5818084 disclosed a kind of trench MOSFET structure rectifiers mostly.As Fig. 1, source region 13 and grid region 12 link together in the MOSFET structure 10, and parasitic diode connects source region 12 and drain region 14.This structure devices is mainly used in that conventional diode or MOSFET shunt to prevent because the few son storage during PN junction positively biased causes burst to puncture and latch-up.Thereby the trenched side-wall of this structure has identical even thin oxide layer with the bottom.For forming low threshold voltage V
Th, the sidewall of groove need have thin oxide layer.Because the sidewall oxide of groove has identical thickness with bottom oxidization layer, so the channel bottom thickness of oxide layer is also very thin, but thin bottom oxidization layer can not be born the high electric field strength under the high reverse voltage.If this structure devices is applied to power rectification, the high electric field strength under the high backward voltage will be born in the channel bottom corner, cause leakage current to increase.
Therefore, how to provide a kind of groove MOSFET power rectifier device, electric field strength high under the high backward voltage can be born in realization channel bottom corner, is those skilled in the art's technical issues that need to address.
The utility model content
In view of this, the utility model provides a kind of groove MOSFET power rectifier device, realizes that electric field strength high under the high backward voltage can be born in the channel bottom corner of groove MOSFET power rectifier device.
In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is as follows:
A kind of groove MOSFET power rectifier device is characterized in that, comprises,
The substrate of first conduction type;
Be positioned at the epitaxial loayer on the described substrate first surface, described epitaxial loayer comprises the first area and centers on the second area of described first area;
Be positioned at several first grooves of the first area of described epitaxial loayer, described first groove extends to described epitaxial loayer inside from the surface of described epitaxial loayer; Wherein, separate by mesa region between described first groove, be filled with doped polycrystalline silicon in described first groove, form gate polysilicon;
Be positioned at the source region of first conduction type on described mesa region surface;
Be positioned at the tagma of second conduction type of below, described source region;
At least one is positioned at the terminal protection ring of second conduction type of described first groove of encirclement of described second area, described terminal protection ring extends to described epitaxial loayer inside from the surface of described epitaxial loayer, and the position of the bottom of described terminal protection ring is lower than the position of described first channel bottom;
Be positioned at the surface of described epitaxial loayer and form first electrode of ohmic contact with described source region, described tagma, described gate polysilicon;
Be positioned at second electrode of the second surface below of described substrate, described second surface is relative with described first surface;
Wherein, described first conduction type and described second conductivity type opposite.
Further, the bottom position of described terminal protection ring is than low 0.3 ~ 3 μ m of bottom position of described first groove.
Further, described first conduction type is N-type, and described second conduction type is the P type.
Epitaxial loayer on the utility model substrate comprises the first area and centers on the second area of first area; by form several first grooves in the first area; form the terminal protection ring that at least one surrounds second conduction type of first groove at second area, the position of the bottom of this terminal protection ring in epitaxial loayer is lower than the position of bottom in epitaxial loayer of first groove.Because the second area of epitaxial loayer is around the first area of epitaxial loayer, so this terminal protection ring can surround the first channel bottom corner.When having the high electric field strength under the high backward voltage around first groove, the terminal protection ring of second conduction type surrounds the first channel bottom corner, has improved the ability that the high electric field strength under the high backward voltage is born in the first channel bottom corner.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the circuit diagram of applied power rectifying device in the prior art;
Fig. 2 is the plane graph of the described groove MOSFET power rectifier device of the utility model embodiment;
Fig. 3 is the profile of the described groove MOSFET power rectifier device of the utility model embodiment.
For the ease of understanding the utility model, below Reference numeral is done an explanation:
20: substrate, 21: epitaxial loayer, 22: field oxide; 30: the first grooves, 31: gate oxide, 33: mesa region; 42: polysilicon gate, 51: terminal protection ring, 53: the tagma; 54: the source region; 55: silicon dioxide oxide layer, 60: through hole, 61: tungsten; 70: the first electrodes, 71: the second electrodes.
Embodiment
For the ease of those skilled in the art's understanding, specify the concrete structure of described groove MOSFET power rectifier device manufacture method and groove MOSFET power rectifier device below in conjunction with accompanying drawing.
A lot of details have been set forth in the following description so that fully understand the utility model, but the utility model can also adopt other to be different from alternate manner described here and implement, those skilled in the art can do similar popularization under the situation of the utility model intension, so the utility model is not subjected to the restriction of following public specific embodiment.
Secondly, the utility model is described in detail in conjunction with schematic diagram, when the utility model embodiment is described in detail in detail; for ease of explanation; the profile of expression device architecture can be disobeyed general ratio and be done local the amplification, and described schematic diagram is example, and it should not limit the scope of the utility model protection at this.The three dimensions size that in actual fabrication, should comprise in addition, length, width and the degree of depth.
The epitaxial loayer of making among the utility model embodiment on the substrate of groove MOSFET power rectifier device comprises two zones: first area and around the second area of first area.Wherein, the first area is device area, and second area is terminal protection ring zone.Referring to Fig. 2, Fig. 2 is the plane graph of the described groove MOSFET power rectifier device of the utility model embodiment.Find out that from this figure the terminal protection ring 51 of second conduction type is positioned at the outer peripheral areas of epitaxial loayer, its device such as device component tagma 53 are positioned at the zone line of this epitaxial loayer.
See also figure, Fig. 3 is the described groove MOSFET power rectifier device of the utility model embodiment profile.
This MOSFET power rectifier device comprises:
N-type substrate 20;
Be positioned at the epitaxial loayer 21 on substrate 20 first surfaces, this epitaxial loayer 21 comprises the first area and centers on the second area of described first area;
Be positioned at several first grooves 30 of the first area of this epitaxial loayer 21, this first groove 30 extends to this epitaxial loayer 21 inside from the surface of this epitaxial loayer 21; Wherein, separate by mesa region 33 between this first groove 30, be filled with doped polycrystalline silicon in this first groove 30, form gate polysilicon 42;
Be positioned at the N-type source region 54 on these mesa region 33 surfaces;
Be positioned at the tagma 53 of the P type of these 54 belows, source region;
At least one is positioned at the P type terminal protection ring 51 of this first groove 30 of encirclement of this second area, this terminal protection ring 51 extends to this epitaxial loayer 21 inside from the surface of epitaxial loayer 21, and the position of the bottom of this terminal protection ring 51 is lower than the position of these first groove, 30 bottoms;
Be positioned at the surface of this epitaxial loayer 21 and form first electrode 70 of ohmic contact with source region 54, tagma 53, gate polysilicon 42;
Be positioned at second electrode 71 of the second surface below of substrate 20, described second surface is relative with described first surface.
Particularly, N-type substrate 20 can be N-type heavy doping substrate.
In order to improve the performance of device, the lightly doped N-type epitaxial loayer 21 of one deck is positioned on the first surface of substrate 20.This epitaxial loayer 21 can adopt method well known in the art to form.Wherein this epitaxial loayer 21 comprises the first area and around the second area of this first area.
First groove 30 is formed at the first area of epitaxial loayer 21.In fact can so understand, the size of the first area of epitaxial loayer 21 is to be determined by the device of MOSFET power rectifier device.First area at epitaxial loayer makes device.
The forming process of first groove 30 can for: at first form one deck band figure photoresists by photo etched mask at field oxide 22, and remove field oxide 22 in the figure by etching process.Remove photoresist layer then, go out several first grooves 30 and form between mesa region 33, the first grooves 30 in epitaxial loayer 21 etched inside by the reactive ion etching method and separate by mesa region 33.
Adopt dry method or wet processing at sidewall and the bottom growth layer of even gate oxide 31 of first groove 30, the thickness of this gate oxide 31 can for
Need to prove that in the present embodiment, the thickness of the sidewall of first groove 30 and the gate oxide of bottom can equate, also can be unequal.In order to make first groove 30 form lower threshold voltage V
Th, and in order to realize that the first channel bottom corner can bear high electric field strength, preferred, the thickness of the gate oxide 31 of bottom is greater than the thickness of the gate oxide 31 of sidewall.
The thickness that is filled in the polysilicon gate 42 in first groove 30 can be 10-80nm.
P type terminal protection ring 51 is positioned at the second area of epitaxial loayer and surrounds first groove 30.The following method that can adopt of this P type terminal protection ring 51 forms:
P type impurity boron is injected into the second area of epitaxial loayer 21 from the surface of epitaxial loayer 21, the energy of employing is 20-300KeV, and dosage is E13-16/cm
2Activate and advance this P type boron impurity to form P type terminal protection ring 51 then.Need to prove; for P type terminal protection ring 51 can be arrived than the bottom position of first groove 30 low position also; need to adopt higher activationary temperature and long time, the activationary temperature that adopts in the present embodiment is 1000 ~ 1200 ° of C, and the time is 1 ~ 2 hour.
Finally; this P type terminal protection ring 51 can surround first groove 30, and this P type terminal protection ring 51 extends to described epitaxial loayer 21 inside from the surface of this epitaxial loayer, and the position of the bottom of described terminal protection ring 51 is darker than the position of described first groove 30 bottoms; more preferably, dark 0.3 ~ 3 μ m.Because; P type terminal protection ring 51 be positioned at first groove 30 around; and the bottom position of P type terminal protection ring 51 is lower than the bottom position of first groove 30; so; P type terminal protection ring 51 can surround first groove, 30 bottom corner, forms a guard ring to first groove, 30 bottom corner.Like this, under the high electric field strength under high backward voltage, because the existence of terminal protection ring 51, first groove, 30 bottom corner can directly not contact high electric field strength, and first groove, 30 bottom corner can be born high electric field strength.Even so under the situation of the high electric field strength under high backward voltage; this groove MOSFET power rectifier device of making can not leak electricity yet; so P type terminal protection ring 51 that this embodiment provides has improved the ability that first groove, 30 bottom corner are born the high electric field strength under the high backward voltage; reduce the possibility of element leakage, improved the performance of device.
Need to prove that this terminal protection ring 51 is not limited to one the situation of this exemplifying embodiment, this terminal protection ring 51 can for one also can be for a plurality of, for example 2,3,5 etc.The terminal protection ring is more many, and is more strong to the protective effect of first groove.
In addition; can also form this terminal protection ring 51 in the first area; and this terminal protection ring 51 surrounds one or several first grooves 30 of first area; thereby form as much as possible even each groove are all protected; thereby further improve the ability that channel bottom bears the high electric field strength under the high backward voltage, reduce leakage current.
The formation method in P type tagma 53 can adopt method well known in the art to form, for example can for, be mask with the photoresist figure; boron impurity is injected in first area to epitaxial loayer 21; the injection energy is 20-300KeV, and the dosage when the dosage ratio forms terminal protection ring 51 is low, is generally E12 ~ 15/cm
2, form P type tagma 53 with the lower zone in mesa region 33.
The formation method in N-type source region 54 also can adopt method well known in the art to form, for example can for, inject arsenic in the first area of epitaxial loayer 21 or phosphorus impurities forms source region 54 with the surf zone in mesa region 33.Inject metering in this process and be E13-16/cm
2, the injection energy is 10-60KeV.
Then, remove photoresist, adopt the method for heating, activate the boron impurity and arsenic or the phosphorus impurities that inject, finally to form P type tagma 53 and N-type source region 54 respectively.
First electrode 70 forms ohmic contact by through hole 60 and described source region 54, tagma 54 and gate polysilicon 42.Wherein, being filled with tungsten 61, the first electrodes 70 in the described through hole 60 can adopt metals such as Ti, TiN, Al, Ni, Ag or metallic compound or its compound to be made.
Adopt second electrode 71 that can form at the second surface of substrate 20 with first electrode, 70 identical materials.
The method that present embodiment forms electrode can adopt this area routine techniques means, and those skilled in the art are known at an easy rate, do not repeat them here.
Need to prove that above-described embodiment is that N-type is that example describes with the conduction type of substrate, in fact, when the conduction type of substrate is the P type, is equally applicable to design of the present utility model.When the conduction type of substrate was the P type, at this moment, the conduction type in source region 54 correspondingly became the P type, and was positioned at the tagma 53 of 54 belows, source region and the conduction type of terminal protection ring 51 also correspondingly becomes N-type.
More than to groove MOSFET power rectifier device provided by the utility model and manufacture method thereof, be described in detail, used specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present utility model and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present utility model, the part that all can change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model.
Claims (3)
1. a groove MOSFET power rectifier device is characterized in that, comprise,
The substrate of first conduction type;
Be positioned at the epitaxial loayer on the described substrate first surface, described epitaxial loayer comprises the first area and centers on the second area of described first area;
Be positioned at several first grooves of the first area of described epitaxial loayer, described first groove extends to described epitaxial loayer inside from the surface of described epitaxial loayer; Wherein, separate by mesa region between described first groove, be filled with doped polycrystalline silicon in described first groove, form gate polysilicon;
Be positioned at the source region of first conduction type on described mesa region surface;
Be positioned at the tagma of second conduction type of below, described source region;
At least one is positioned at the terminal protection ring of second conduction type of described first groove of encirclement of described second area, described terminal protection ring extends to described epitaxial loayer inside from the surface of described epitaxial loayer, and the position of the bottom of described terminal protection ring is lower than the position of described first channel bottom;
Be positioned at the surface of described epitaxial loayer and form first electrode of ohmic contact with described source region, described tagma, described gate polysilicon;
Be positioned at second electrode of the second surface below of described substrate, described second surface is relative with described first surface;
Wherein, described first conduction type and described second conductivity type opposite.
2. groove MOSFET power rectifier device according to claim 1 is characterized in that, the bottom position of described terminal protection ring is than low 0.3 ~ 3 μ m of bottom position of described first groove.
3. groove MOSFET power rectifier device according to claim 1 is characterized in that, described first conduction type is N-type, and described second conduction type is the P type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320071888 CN203179885U (en) | 2013-02-07 | 2013-02-07 | Trench MOSFET power rectification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320071888 CN203179885U (en) | 2013-02-07 | 2013-02-07 | Trench MOSFET power rectification device |
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| Publication Number | Publication Date |
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| CN203179885U true CN203179885U (en) | 2013-09-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201320071888 Expired - Lifetime CN203179885U (en) | 2013-02-07 | 2013-02-07 | Trench MOSFET power rectification device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117308A (en) * | 2013-02-07 | 2013-05-22 | 上海新进半导体制造有限公司 | Groove MOSFET (metal-oxide-semiconductor field-effect transistor) power rectifier and manufacturing method thereof |
| CN106409827A (en) * | 2015-07-28 | 2017-02-15 | 无锡华润华晶微电子有限公司 | Rectifying device and preparation method thereof |
-
2013
- 2013-02-07 CN CN 201320071888 patent/CN203179885U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117308A (en) * | 2013-02-07 | 2013-05-22 | 上海新进半导体制造有限公司 | Groove MOSFET (metal-oxide-semiconductor field-effect transistor) power rectifier and manufacturing method thereof |
| CN106409827A (en) * | 2015-07-28 | 2017-02-15 | 无锡华润华晶微电子有限公司 | Rectifying device and preparation method thereof |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20210204 Address after: No. 1600, Zixing Road, Minhang District, Shanghai 200241 Patentee after: BCD (SHANGHAI) MICRO-ELECTRONICS Ltd. Address before: 200241 no.800, Yishan Road, Xuhui District, Shanghai Patentee before: BCD Semiconductor Manufacturing Limited |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130904 |