CN201749852U

CN201749852U - Fast ultra-junction longitudinal double diffusion metal oxide semiconductor tube

Info

Publication number: CN201749852U
Application number: CN201020507550XU
Authority: CN
Inventors: 钱钦松; 祝靖; 孙伟锋; 陆生礼; 时龙兴
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2010-08-27
Filing date: 2010-08-27
Publication date: 2011-02-16
Anticipated expiration: 2020-08-27

Abstract

The utility model provides a fast ultra-junction longitudinal double diffusion metal oxide semiconductor tube, comprising: a primitive cell region, a terminal region disposed at the out periphery of a chip, and a transition region disposed between the primitive cell region and the terminal region, drain electrode metal is disposed at the bottom of the primitive cell region, the transition region, and the terminal region (III), a heavily doped n-type silicon substrate is disposed on the drain electrode metal as a drain region of the chip, a n-type doped epitaxial layer is disposed on the heavily doped n-type silicon substrate, a discontinuous p-type doped columnar semiconductor region is disposed in the n-type doped epitaxial layer. The metal oxide semiconductor tube is characterized in that, an n-type heavily doped semiconductor region is disposed in the second p-type doped semiconductor region in the transition region, and the surface of the n-type heavily doped semiconductor region is provided with a contact hole connected with the metal layer, forming the ground contact electrode of the chip. The metal oxide semiconductor tube in the utility model is advantaged by, under the condition of not increasing technology cost or not changing main parameters of device, capability of effectively reducing reverse recovery charge of device and improving reverse recovery characteristics.

Description

Quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube

Technical field

The utility model relates to a kind of silicon system high-voltage power metal oxide semiconductor device, says more accurately, relates to a kind of silicon system high pressure ultra-junction longitudinal double-diffused metal oxide semiconductor field-effect transistor.

Background technology

At present, power device in the application in fields such as daily life, production more and more widely, power metal oxide semiconductor field-effect transistor particularly, because they have switching speed, less drive current, the safety operation area of broad faster, therefore be subjected to numerous researchers' favor.Nowadays, power device is just towards improving operating voltage, increase operating current, reducing conducting resistance and integrated direction fast development.In numerous power metal oxide semiconductor field-effect transistor devices, especially in vertical power metal oxide semiconductor field-effect transistor, the utility model of super pn junction p n power device, it overcomes the contradiction between conventional power mos field effect transistor conducting resistance and the puncture voltage, changed the conventional power device and relied on the withstand voltage structure of drift layer, but adopted a kind of " super-junction structure "---the form that P type, N type silicon semiconductor material are alternately arranged mutually in the drift region.This structure has been improved puncture voltage and the difficult situation about taking into account simultaneously of conducting resistance, when off-state, because the depletion region electric field in P type post and the N type post produces mutual compensating effect, the doping content that makes P type post and N type post can be done very highly and can not cause the decline of device electric breakdown strength.During conducting, the doping of this high concentration obviously reduces the conducting resistance of device.Because this unique device structure of ultra-junction longitudinal double-diffused metal oxide semiconductor field-effect transistor, make its electrical property obviously be better than the conventional power mos field effect transistor, therefore this technology is called the technical milestone of power metal oxide semiconductor field-effect transistor by people.And improved the whole withstand voltage of device by the structure of optimizing and improve the terminal edges zone of entire device.

Yet, with reference to Fig. 2, in the tradition ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube, the junction area of body diode enlarges markedly with respect to the longitudinal double diffusion metal oxide semiconductor field effect transistor, when forward bias is leaked in the source, owing to injecting a large amount of minority carriers and store a large amount of electric charges in the knot both sides of body diode, thereby the QRR when causing device source to leak reverse bias is a lot, and p post and n post just can exhaust when lower reverse biased fully, when so reverse bias is leaked in the source, QRR just must be eliminated at short notice fully, the reverse recovery current of body diode of causing flowing through changes very fast, i.e. the existence of body diode has restricted the reverse recovery characteristic of device.

The utility model content

The utility model is at the deficiencies in the prior art, a kind of structure of quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube is proposed, this structure can be on the basis that does not influence the device withstand voltage performance, reduced the QRR of body diode, thereby the raising reverse recovery characteristic has reduced the switching loss of device.

The utility model adopts following technical scheme:

A kind of quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube, comprise: cellular region, be located at the termination environment of chip outermost and the transition region between cellular region and termination environment, bottom in cellular region, transition region and termination environment is provided with drain metal, on drain metal, be provided with heavy doping n type silicon substrate,, on heavy doping n type silicon substrate, be provided with n type doped epitaxial layer as the drain region of this chip, in n type doped epitaxial layer, be provided with and be interrupted discontinuous p type doping column semiconductor region

Be provided with a p type doped semiconductor area on the p type doping column semiconductor region in cellular region, and a p type doped semiconductor area is positioned at n type doped epitaxial layer, in a p type doped semiconductor area, be provided with a p type heavily-doped semiconductor contact zone and n type heavily-doped semiconductor source region, in a p type heavily-doped semiconductor contact zone and n type heavily-doped semiconductor source region be provided with gate oxide with exterior domain, above gate oxide, be provided with polysilicon gate, on polysilicon gate, be provided with the first type field oxide, on a n type heavily-doped semiconductor source region and a p type heavily-doped semiconductor contact zone, be connected with source metal

Be provided with the 2nd p type doped semiconductor area in the n type doped epitaxial layer in transition region, and the 2nd p type doped semiconductor area has covered p type doping column semiconductor regions whole in the transition region, in the 2nd p type doped semiconductor area, be provided with two the 2nd p type heavily-doped semiconductor contact zones and n type heavily-doped semiconductor district, and the 2nd p type heavily-doped semiconductor contact zone of contiguous cellular region is arranged in the top of the p type doping column semiconductor region adjacent with cellular region of transition region, n type heavily-doped semiconductor district is arranged in the top of transition region second p type doping column semiconductor region from the left side, the 2nd p type heavily-doped semiconductor contact zone on right side is positioned at the zone line in n type heavily-doped semiconductor district, in the 2nd p type doped semiconductor area, the 2nd p type heavily-doped semiconductor contact zone and surface, n type heavily-doped semiconductor district are provided with the second type field oxide, being provided with contact hole on the surface, the 2nd p type heavily-doped semiconductor contact zone that is positioned at the inner and contiguous cellular region of the 2nd p type doped semiconductor area links to each other with source metal

In the termination environment, be provided with n type heavily-doped semiconductor district in the upper right corner of n type doped epitaxial layer, be provided with the second type field oxide on the surface, termination environment,

It is characterized in that, be provided with n type heavily-doped semiconductor district in the 2nd p type doped semiconductor area in transition region, and be provided with contact hole on surface, n type heavily-doped semiconductor district and link to each other, form the ground contact electrode of chip with metal level.

Compared with prior art, the utlity model has following advantage:

(1) with reference to Fig. 3, the utility model structure is four port devices, the source electrode that has except that traditional devices, the drain and gate, this device also contacts the utmost point with existing, and this electrode ground connection all the time when the device operate as normal, in system applies, do not need extra biasing circuit to provide bias voltage, therefore can not increase the difficulty of corresponding system design for it.

(2) with reference to Fig. 3, diode shown in the dotted line is the body diode that is made of a p type doped semiconductor area 5, the 2nd p type doped semiconductor area 6 and p type doping column semiconductor region 4 and n type doped epitaxial layer 3, and the diode shown in the solid line is by the 2nd p type heavily-doped semiconductor contact zone 8 that is arranged in the contiguous cellular region of transition region II and the pn junction diode that n type heavily-doped semiconductor district 10 constitutes.When leaking forward bias in the source, two diodes all are in the forward bias state, so the pn junction diode during afterflow shown in the dotted line is shared one part of current with the conducting simultaneously of the body diode shown in the solid line time, the electric current of body diode of flowing through during conducting like this reduces, the minority carrier that makes the knot both sides inject reduces, be that QRR reduces, thereby improve reverse recovery characteristic.

When (3) leaking reverse bias in the source, with reference to Fig. 3, the equal connecting to neutral current potential in pn junction diode two ends shown in the solid line is equivalent to short circuit, cuts little ice, and with reference to Fig. 6, the puncture voltage of this structure is not compared with traditional structure and can be reduced.

(4) metal level can extend to the right as field plate in the utility model structure, because metal level is the connecting to neutral current potential fixedly, when this structure is leaked reverse bias in the source, can accelerate depletion layer and launch to edge termination region, improve horizontal withstand voltage level, and then improve the integral device withstand voltage properties.

Description of drawings

Fig. 1 is the cross-sectional view of the quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube of the utility model.

Fig. 2 is the cross-sectional view of traditional ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube.

Fig. 3 is equivalent structure figure of the present utility model, diode shown in the dotted line is the body diode that is made of a p type doped semiconductor area 5, the 2nd p type doped semiconductor area 6 and p type doping column semiconductor region 4 and n type doped epitaxial layer 3, and the diode shown in the solid line is by the 2nd p type heavily-doped semiconductor contact zone 8 that is arranged in the contiguous cellular region of transition region II and the pn junction diode that n type heavily-doped semiconductor district 10 constitutes.

Fig. 4 is the process simulation comparison diagram of cellular region and transition region in the utility model and the traditional structure, (a) represent the process simulation figure of the utility model structure cellular region and transition region, (b) the process simulation figure of a part of transition region in the utility model structure after representative is amplified (c) represents the process simulation figure of cellular region and transition region in the traditional structure.

Fig. 5 is the equipotential lines distribution map when cellular region and transition region are in the source and leak reverse-bias state in the utility model and the traditional structure, (a) represent the utility model structure equipotential lines to distribute, and (b) represents the distribution of traditional structure equipotential lines.

Fig. 6 is the reverse breakdown curve comparison diagram of the utility model and traditional structure.

Fig. 7 is the body diode reverse recovery characteristics curve comparison diagram of the utility model and traditional structure.

Embodiment

With reference to Fig. 1; A kind of rapid superjunction; Comprise: cellular region I; Be located at the termination environment III of chip outermost and the transition region II between cellular region I and termination environment III; Bottom at cellular region I, transition region II and termination environment III is provided with drain metal 1; Be provided with heavy doping N-shaped silicon substrate 2 in drain metal 1; Drain region as this chip; Be provided with N-shaped doped epitaxial layer 3 at heavy doping N-shaped silicon substrate 2; In N-shaped doped epitaxial layer 3, be provided with and be interrupted discontinuous p-type doping column semiconductor region 4

Be provided with a p type doped semiconductor area 5 on the p type doping column semiconductor region 4 in cellular region I, and a p type doped semiconductor area 5 is positioned at n type doped epitaxial layer 3, in a p type doped semiconductor area 5, be provided with a p type heavily-doped semiconductor contact zone 7 and n type heavily-doped semiconductor source region 9, be provided with gate oxide 12 in a p type heavily-doped semiconductor contact zone 7 and n type heavily-doped semiconductor source region 9 with exterior domain, above gate oxide 12, be provided with polysilicon gate 13, on polysilicon gate 13, be provided with the first type field oxide 14, on a n type heavily-doped semiconductor source region 9 and a p type heavily-doped semiconductor contact zone 7, be connected with source metal 16

Be provided with the 2nd p type doped semiconductor area 6 in the n type doped epitaxial layer 3 in transition region II, and the 2nd p type doped semiconductor area 6 has covered p type doping column semiconductor regions 4 whole among the transition region II, in the 2nd p type doped semiconductor area 6, be provided with two the 2nd p type heavily-doped semiconductor contact zones 8 and n type heavily-doped semiconductor district 10, and the 2nd p type heavily-doped semiconductor contact zone 8 of contiguous cellular region is arranged in the top of the p type doping column semiconductor region 4 adjacent with cellular region I of transition region II, n type heavily-doped semiconductor district 10 is arranged in the top of transition region II second p type doping column semiconductor region 4 from the left side, the 2nd p type heavily-doped semiconductor contact zone 8 on right side is positioned at the zone line in n type heavily-doped semiconductor district 10, in the 2nd p type doped semiconductor area 6, the 2nd p type heavily-doped

semiconductor contact zone

8 and 10 surfaces, n type heavily-doped semiconductor district are provided with the second type field oxide 15, being provided with contact hole on 8 surfaces, the 2nd p type heavily-doped semiconductor contact zone that are positioned at the 2nd p type doped semiconductor area 6 inner and contiguous cellular region links to each other with source metal 16

In the II1 of termination environment, be provided with n type heavily-doped semiconductor district 11 in the upper right corner of n type doped epitaxial layer 3, be provided with the second type field oxide 15 on III surface, termination environment,

It is characterized in that, be provided with n type heavily-doped semiconductor district 10 in the 2nd p type doped semiconductor area 6 in transition region II, and be provided with contact hole on 10 surfaces, n type heavily-doped semiconductor district and link to each other, form the ground contact electrode of chip with metal level 17.

Also adopt following technical measures further to improve performance of the present utility model in the present embodiment:

This chip is four port devices, and metal level 17 has constituted the ground contact electrode of chip, and metal level 17 can extend to the right as field plate and use, and the length of extension is by the withstand voltage size decision of chip.

The degree of depth of the 2nd p type heavily-doped semiconductor contact zone 8 that is positioned at n type heavily-doped semiconductor district 10 zone lines is greater than the degree of depth in n type heavily-doped semiconductor district 10, and injects window surface at p type impurity and still show as n type heavily-doped semiconductor district 10.

The number of p type doping column semiconductor region 4 is by designed transistorized requirement of withstand voltage decision among transition region II and the termination environment III.

The width of p type doping column semiconductor region 4 and doping content equate, and the spacing between the width of p type doping column semiconductor region 4 and the p type doping column semiconductor region 4 is adjustable, and can in transition region II and termination environment III, adjust the ratio of spacing between the width of p type doping column semiconductor region 4 and the p type doping column semiconductor region 4 separately, to obtain different voltage endurances.

The distance of the lower surface of p type doping column semiconductor region 4 and the upper surface of heavy doping n type silicon substrate 2 is adjustable.

With reference to Fig. 6, n type heavily-doped semiconductor district 10 in having used the utility model, and be provided with on 10 surfaces, n type heavily-doped semiconductor district that contact hole links to each other with metal level 17 and all the time after the structure of ground connection, the puncture voltage of device is not compared with traditional structure and reduced.

The utility model adopts following method to prepare:

1, selects the substrate of a heavy doping n type silicon chip as device, epitaxial growth one deck light dope n type epitaxial loayer on heavy doping n type substrate then.

2, inject boron at surface ion then, and annealing pushes away trap, form p type tagma, carry out cutting then and fill p type silicon, form p type post.

3, grow then field oxide, gate oxide, deposit polysilicon and etching form polysilicon gate then.

4, phosphonium ion injects the n type source region of formation cellular region and the heavy doping n type zone of transition region and termination environment then.

5, carry out surface passivation then, and carve contact hole, inject the boron ion then and form heavy doping p type body contact zone.Then at tow sides deposit aluminium and carry out etching all, form drain metal, source metal with contact utmost point metal.

Claims

1. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube, comprise: cellular region (I), be located at the termination environment (III) of chip outermost and be positioned at cellular region (I) and termination environment (III) between transition region (II), at cellular region (I), the bottom of transition region (II) and termination environment (III) is provided with drain metal (1), on drain metal (1), be provided with heavy doping n type silicon substrate (2), drain region as this chip, on heavy doping n type silicon substrate (2), be provided with n type doped epitaxial layer (3), in n type doped epitaxial layer (3), be provided with and be interrupted discontinuous p type doping column semiconductor region (4)

Be provided with a p type doped semiconductor area (5) on the p type doping column semiconductor region (4) in cellular region (I), and a p type doped semiconductor area (5) is positioned at n type doped epitaxial layer (3), in a p type doped semiconductor area (5), be provided with a p type heavily-doped semiconductor contact zone (7) and n type heavily-doped semiconductor source region (9), be provided with gate oxide (12) in a p type heavily-doped semiconductor contact zone (7) and n type heavily-doped semiconductor source region (9) with exterior domain, be provided with polysilicon gate (13) in gate oxide (12) top, on polysilicon gate (13), be provided with the first type field oxide (14), on a n type heavily-doped semiconductor source region (9) and a p type heavily-doped semiconductor contact zone (7), be connected with source metal (16)

Be provided with the 2nd p type doped semiconductor area (6) in the n type doped epitaxial layer (3) in transition region (II), and the 2nd p type doped semiconductor area (6) has covered p type doping column semiconductor regions (4) whole in the transition region (II), in the 2nd p type doped semiconductor area (6), be provided with two the 2nd p type heavily-doped semiconductor contact zones (8) and n type heavily-doped semiconductor district (10), and the 2nd p type heavily-doped semiconductor contact zone (8) of contiguous cellular region is arranged in the top of the p type doping column semiconductor region (4) adjacent with cellular region (I) of transition region (II), n type heavily-doped semiconductor district (10) is arranged in the top of transition region (II) second p type doping column semiconductor region (4) from the left side, the 2nd p type heavily-doped semiconductor contact zone (8) on right side is positioned at the zone line in n type heavily-doped semiconductor district (10), in the 2nd p type doped semiconductor area (6), the 2nd p type heavily-doped semiconductor contact zone (8) and surface, n type heavily-doped semiconductor district (10) are provided with the second type field oxide (15), being provided with contact hole on the surface, the 2nd p type heavily-doped semiconductor contact zone (8) that is positioned at the inner and contiguous cellular region of the 2nd p type doped semiconductor area (6) links to each other with source metal (16)

In termination environment (III), be provided with n type heavily-doped semiconductor district (11) in the upper right corner of n type doped epitaxial layer (3), (III) surface is provided with the second type field oxide (15) in the termination environment,

It is characterized in that, be provided with n type heavily-doped semiconductor district (10) in the 2nd p type doped semiconductor area (6) in transition region (II), and be provided with contact hole on surface, n type heavily-doped semiconductor district (10) and link to each other, form the ground contact electrode of chip with metal level (17).

2. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube according to claim 1, it is characterized in that this chip is four port devices, metal level (17) has constituted the ground contact electrode of chip, and metal level (17) can extend to the right as the field plate use, and the length of extension is by the withstand voltage size decision of chip.

3. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube according to claim 1, the degree of depth of the 2nd p type heavily-doped semiconductor contact zone (8) that it is characterized in that being positioned at n type heavily-doped semiconductor district (10) zone line is greater than the degree of depth in n type heavily-doped semiconductor district (10), and injects window surface at p type impurity and still show as n type heavily-doped semiconductor district (10).

4. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube according to claim 1, the number that it is characterized in that p type doping column semiconductor region (4) among transition region (II) and termination environment (III) is by designed transistorized requirement of withstand voltage decision.

5. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube according to claim 1, the width and the doping content that it is characterized in that p type doping column semiconductor region (4) equate, and the spacing between the width of p type doping column semiconductor region (4) and the p type doping column semiconductor region (4) is adjustable, and can in transition region (II) and termination environment (III), adjust the ratio of spacing between the width of p type doping column semiconductor region (4) and the p type doping column semiconductor region (4) separately, to obtain different voltage endurances.

6. quick ultra-junction longitudinal bilateral diffusion metal oxide semiconductor tube according to claim 1 is characterized in that the distance of upper surface of the lower surface of p type doping column semiconductor region (4) and heavy doping n type silicon substrate (2) is adjustable.