CN101740392B - LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistor, semiconductor device and manufacture method thereof - Google Patents
LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistor, semiconductor device and manufacture method thereof Download PDFInfo
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- CN101740392B CN101740392B CN2008102035387A CN200810203538A CN101740392B CN 101740392 B CN101740392 B CN 101740392B CN 2008102035387 A CN2008102035387 A CN 2008102035387A CN 200810203538 A CN200810203538 A CN 200810203538A CN 101740392 B CN101740392 B CN 101740392B
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Abstract
The invention relates to an LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistor, a semiconductor device and a manufacture method thereof, wherein the manufacture method of the LDMOS transistor comprises the steps of: forming a deep-doped well in a semiconductor substrate; forming an isolation structure in the deep-doped well, wherein the isolation structure is arranged between a source electrode and a drain electrode and is close to the drain electrode; forming a first ion doping area in the deep-doped well; and forming a second ion doping area in the deep-doped well, wherein a space is reserved between the first ion doping area and the second ion doping area. By forming the deep-doped well which has the same channel conduction type with the LDMOS transistor to be formed in the semiconductor substrate, the invention can obtain higher breakdown voltage.
Description
Technical field
The present invention relates to technical field of semiconductors, particularly ldmos transistor, semiconductor device and manufacturing approach thereof with ldmos transistor.
Background technology
In the development of power integrated circuit; For the single-chip processing procedure that power switch and control circuit is combined and develop; Especially at present be used to make horizontal secondary diffused metal oxide emiconductor (the lateral double diffusion MOS of monolithic integrated circuit; LDMOS) processing procedure is a main flow trend.The LDMOS processing procedure is to carry out planar diffusion (planar diffusion) in the surface of semiconductor substrate so that form horizontal main current path; Because LDMOS is with the manufacturing of typical IC processing procedure; Therefore control circuit and LDMOS can be incorporated on the single-chip power supply IC; The LDMOS processing procedure adopts surface field reduction (reduced surface electric field; RESURE) technology and low thickness extension (EPI) or N type well region (N-well) can reach the target of high voltage and low conduction impedance.
The LDMOS device is a kind of FET device (FET) that is similar to traditional F ET device; All be included in and form a pair of source/drain region of being separated in the Semiconductor substrate by channel region; And form gate electrode in the channel region top successively; Yet; The LDMOS device is different with traditional F ET device, and to be that pair of source territory in the traditional FET device is processed with gate electrode symmetrical, and the drain region in the LDMOS device forms further from gate electrode than the source region, and the drain region is formed in order in the dopant well (having and the drain region identical polar) of separating channel region and drain region simultaneously.
Prior art discloses a kind of LDMOS of having integrated circuit technique, and concrete structure is as shown in Figure 1, comprising: the N-trap 112 of silicon is by border 113 and 111 insulation of P-trap.P-trap 111 by the surface, top to extending below and comprise N+ zone 117, and with 117 and the interface of P-trap 112 between distance L 110 confirm this raceway groove; N+ zone 117 provides source electrode 125 and has drained 130 both contact areas; Along with applying of polysilicon gate 116 (below the gate oxide that is not represented for clarity) positive voltage VG; Electric current can be passed raceway groove and flowed into N+117, P-trap 111 and N-trap 112 by source electrode 125, and is gathered in N+117 by drain electrode 130; Metal Contact window 115 is given short circuit to carry out ohmic contact with N+ zone 117 and P+ zone 119, so will allow source current through P-trap 111, and cools off by fin (heat sink).Most LDMOS structure builds on the substrate with one or more other device architectures, and in high-voltage applications, the effect of oxide in field 14 provides insulation and through reducing electric field density to improve puncture voltage.
, application number can also find more information relevant in being 200510001857.6 one Chinese patent application with technique scheme.
Prior art also discloses a kind of p-LDMOS structure, and is as shown in Figure 2, comprises the dark n type dopant well 201 that is positioned on the Semiconductor substrate, wherein is formed with fleet plough groove isolation structure 202, N-zone 203, P-zone 204, source electrode 208 and drains 209; Be positioned at the gate dielectric layer 205 on the Semiconductor substrate; Polysilicon gate 206 and the side wall 207 that is positioned at polysilicon gate 206 both sides.Along with applying of positive voltage VG on the polysilicon gate 206, electric current can be passed raceway groove and flowed into N-zone 203, dark n type dopant well 201, P-zone 204 by source electrode 208, and is gathered in drain electrode 209.
In this technical scheme; P-zone 204 is as the drift regions of drain electrode 209, and length of effective channel is among Fig. 2 shown in the DLL, under grid voltage; Form back-biased diode between P-zone 204 and the P-zone 204; Depletion region is narrower, and the withstand voltage degree of ldmos transistor is lower, causes can occurring snap back (snapback) phenomenon very soon in the I-V characteristic curve of ldmos transistor; And, form in 204 processes of P-zone, if mask has deviation, do not surround fleet plough groove isolation structure 202 fully such as P-zone 204, cause threshold voltage too high and influence is actual uses easily; Simultaneously, form P-zone 204 and need inject separately and the separate mask plate, cost is higher.
Summary of the invention
The problem that the present invention solves provides a kind of ldmos transistor, has the semiconductor device and the manufacturing approach thereof of ldmos transistor, with the withstand voltage degree that improves ldmos transistor with reduce cost.
For addressing the above problem, the invention provides a kind of manufacture method of ldmos transistor, comprise the steps: to provide Semiconductor substrate; In said Semiconductor substrate, form dark dopant well; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; In said dark dopant well, form isolation structure, said isolation structure is between source electrode and drain electrode and near drain electrode; In said dark dopant well, form first ion doped region, the conduction type of said first ion doped region is identical with the channel type of ldmos transistor; The degree of depth of said first ion doped region greater than isolation structure bottom and cover drain electrode and cover isolation structure at least be trapped among subregion corresponding in the said dark dopant well outward; In said dark dopant well, form second ion doped region, the conduction type of said second ion doped region is opposite with the channel type of ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
Comprise that also annealing steps, said annealing temperature are 800 to 1100 ℃ after forming said dark dopant well, annealing atmosphere is N
2, annealing time is 1 to 3 hour.
Said first ion doped region injects through ion and forms, and said ion injects and the dopant well of voltage device carries out simultaneously.
The mask pattern that forms the ion mask pattern that injects and the dopant well that forms voltage device of said first ion doped region is positioned on the same mask.
The channel type of said ldmos transistor is the n type; The mask pattern that forms said first ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask, said dark dopant well is the n type.
The channel type of said ldmos transistor is the p type; The figure that forms said first ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask, said dark dopant well is the p type.
Before forming said dark dopant well, also comprise forming dark n type dopant well step, the said dark n type dopant well degree of depth is greater than dark dopant well.
The present invention also provides a kind of ldmos transistor, comprising: the source electrode, drain electrode and the gate dielectric layer that are positioned at Semiconductor substrate; Isolation structure is between source electrode and drain electrode and near drain electrode; First ion doped region is positioned at said Semiconductor substrate, and the conduction type of said first ion doped region is identical with the conduction type of the raceway groove of ldmos transistor; The degree of depth of said first ion doped region greater than isolation structure bottom and cover drain electrode and cover isolation structure at least be trapped among subregion corresponding in the said Semiconductor substrate outward; Second ion doped region is positioned at said Semiconductor substrate, the conductivity type opposite of the conduction type of said second ion doped region and the raceway groove of ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said Semiconductor substrate at least; Have between said second ion doped region and first ion doped region at interval; Also comprise: dark dopant well; The conduction type of said dark dopant well is identical with the conduction type of the raceway groove of ldmos transistor, and covers the subregion of said first ion doped region, second ion doped region and gate dielectric layer correspondence in said Semiconductor substrate.
Also comprise the dark n type dopant well that is positioned at Semiconductor substrate, the said dark n type dopant well degree of depth is greater than dark dopant well.
The present invention also provides a kind of manufacturing approach with semiconductor device of ldmos transistor, comprising: Semiconductor substrate is provided, and said Semiconductor substrate contains high tension apparatus zone and middle voltage device zone; In the Semiconductor substrate in high tension apparatus zone, form dark dopant well; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; In said dark dopant well, form isolation structure, said isolation structure is between source electrode and drain electrode and near drain electrode; In said dark dopant well, form first ion doped region, the conduction type of said first ion doped region is identical with the channel type of said ldmos transistor; The degree of depth of said first ion doped region is greater than the isolation structure bottom; And the outer subregion that is trapped among correspondence in the said dark dopant well that covers drain electrode and cover isolation structure at least; In said dark dopant well, form second ion doped region, the conduction type of said second ion doped region is opposite with the channel type of said ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
Comprise that also annealing steps, said annealing temperature are 800 to 1100 ℃ after forming said dark dopant well, annealing atmosphere is N
2, annealing time is 1 to 3 hour.
Said first ion doped region injects through ion and forms, and said ion injects and the dopant well of voltage device carries out simultaneously.
The mask pattern that forms the ion mask pattern that injects and the dopant well that forms voltage device of said first ion doped region is positioned on the same mask.
The channel type of said ldmos transistor is the n type; The mask pattern that forms said first ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask, said dark dopant well is the n type.
The channel type of said ldmos transistor is the p type; The figure that forms said first ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask, said dark dopant well is the p type.
Before forming said dark dopant well, also comprise forming dark n type dopant well step, the said dark n type dopant well degree of depth is greater than dark dopant well.
A kind of semiconductor device of aforesaid manufacturing.
Compared with prior art, the present technique scheme has the following advantages: through in Semiconductor substrate, forming the identical dark dopant well of channel type with ldmos transistor to be formed, in dark the doping, form first ion doped region and second ion doped region of mutual isolation then; Said first ion doped region is identical with channel type; Second ion doped region and channel type are opposite, and the raceway groove of ldmos transistor is second corresponding under the gate dielectric layer ion doped region, and raceway groove is shorter; Under grid voltage; Form back-biased diode between dark dopant well and first ion doped region and second ion doped region, this district exhausts entirely before puncturing, and can obtain higher puncture voltage; Be that snap back phenomenon in the I-V curve of ldmos transistor moves to right, improve the withstand voltage degree of ldmos transistor; Simultaneously, through increasing the doping content of first ion doped region, can reduce opening resistor (rdson); And; Because first ion doped region that forms is identical with the conduction type of dark dopant well; Even because when forming first ion doped region; Mask in the photoetching process has deviation, does not surround isolation structure fully even does not surround the isolation structure part such as first ion doped region, the too high and actual problem of using of influence of the threshold value that can not cause prior art;
The present technique scheme is also injected to inject with the dopant well ion that forms voltage device through the ion that forms first ion doped region and is carried out simultaneously, avoids in the prior art injection process of extra increase in order to form the drift region, has reduced the technology cost;
The present technique scheme also is arranged on the same mask through the mask pattern of the ion that will form said first ion doped region mask pattern that injects and the dopant well that forms voltage device; Avoid in the prior art mask plate of extra increase in order to form the drift region; Can carry out simultaneously with the dopant well in voltage device zone in the formation simultaneously, reduced the cycle period of technology cost and product;
The present technique scheme is annealed into N through after forming dark dopant well, being 800 to 1100 ℃ in temperature
2Annealing is 1 to 3 hour under the atmosphere, makes the ion distribution in it more even, and can repair the damage in the injection process.
Description of drawings
Fig. 1 is the structural representation of ldmos transistor of the formation of prior art;
Fig. 2 is the structural representation of the another kind of ldmos transistor of prior art;
Fig. 3 is the schematic flow sheet of formation ldmos transistor of the present invention;
Fig. 4 is the transistorized schematic flow sheet of formation p-LDMOS of one embodiment of the present of invention;
Fig. 5 to 8 is transistorized structural representations of formation p-LDMOS of one embodiment of the present of invention;
Fig. 9 is the transistorized I-V characteristic curve of p-LDMOS that adopts structure shown in Figure 2 of the prior art;
Figure 10 is the transistorized I-V characteristic curve of p-LDMOS that adopts method of the present invention to form;
Figure 11 is the transistorized schematic flow sheet of formation n-LDMOS of one embodiment of the present of invention;
Figure 12 to 15 is transistorized structural representations of formation n-LDMOS of one embodiment of the present of invention;
Figure 16 is the transistorized I-V characteristic curve of n-LDMOS that adopts structure shown in Figure 2 of the prior art;
Figure 17 is the transistorized I-V characteristic curve of n-LDMOS that the method for employing forms;
Figure 18 is the structural representation that the formation of one embodiment of the present of invention has the semiconductor device of ldmos transistor.
Embodiment
The present invention is through forming the identical dark dopant well of channel type with ldmos transistor to be formed in Semiconductor substrate; In dark the doping, form first ion doped region and second ion doped region of isolating each other then, said first ion doped region is identical with channel type, and second ion doped region and channel type are opposite; The raceway groove of ldmos transistor is second corresponding under the gate dielectric layer ion doped region; Raceway groove is shorter, under grid voltage, forms back-biased diode between dark dopant well and first ion doped region and second ion doped region; This district exhausts entirely before puncturing; Can obtain higher puncture voltage, promptly the snap back phenomenon in the I-V curve of ldmos transistor moves to right, and improves the withstand voltage degree of ldmos transistor; Simultaneously, through increasing the doping content of first ion doped region, can reduce opening resistor (Rdson); And; Because first ion doped region that forms is identical with the conduction type of dark dopant well; Even because when forming first ion doped region; Mask in the photoetching process has deviation, does not surround isolation structure fully even does not surround the isolation structure part such as first ion doped region, the too high and actual problem of using of influence of the threshold value that can not cause prior art.
The present invention also injects to inject with the dopant well ion that forms voltage device through the ion that forms first ion doped region and carries out simultaneously, avoids in the prior art injection process of extra increase in order to form the drift region, has reduced the technology cost.
The present invention also is arranged on the same mask through the mask pattern of the ion that will form said first ion doped region mask pattern that injects and the dopant well that forms voltage device; Avoid in the prior art mask plate of extra increase in order to form the drift region; Can carry out simultaneously with the dopant well in voltage device zone in the formation simultaneously, reduced the cycle period of technology cost and product.
The present invention is annealed into N through after forming dark dopant well, being 800 to 1100 ℃ in temperature
2Annealing is 1 to 3 hour under the atmosphere, makes the ion distribution in it more even, and can repair the damage in the injection process.
Below through describing specific embodiment in detail according to accompanying drawing, above-mentioned purpose and advantage of the present invention will be clearer:
The present invention at first provides a kind of manufacture method of ldmos transistor; With reference to Fig. 3; Comprise: execution in step S11, Semiconductor substrate is provided, be formed with dark dopant well in the said Semiconductor substrate; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; Execution in step S13 forms isolation structure in said dark dopant well, said isolation structure is between source electrode and drain electrode and near drain electrode; Execution in step S15 forms first ion doped region in said dark dopant well, the conduction type of said first ion doped region is identical with the channel type of ldmos transistor; The degree of depth of said first ion doped region is greater than isolation structure bottom and the peripheral profile that covers drain electrode and cover isolation structure at least corresponding subregion in said dark dopant well; Execution in step S17 forms second ion doped region in said dark dopant well, the conduction type of said second ion doped region is opposite with the channel type of ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
Said first ion doped region injects through ion and forms, and said ion injects and the dopant well of voltage device carries out simultaneously.
The mask pattern that forms the ion mask pattern that injects and the dopant well that forms voltage device of said first ion doped region is positioned on the same mask.
The channel type of said ldmos transistor can be the n type; Also can be the p type, the present invention at first provides a kind of p-LDMOS transistorized formation method, with reference to Fig. 4; Comprise: execution in step S101; Semiconductor substrate is provided, is formed with the dark dopant well of p type in the said Semiconductor substrate, ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; Execution in step S103 forms isolation structure in said dark dopant well, said isolation structure is between source electrode and drain electrode and near drain electrode; Execution in step S105 forms p type first ion doped region in said dark dopant well; The degree of depth of said first ion doped region is greater than isolation structure bottom and the peripheral profile that covers drain electrode and cover isolation structure at least corresponding subregion in said dark dopant well; Execution in step S107, second ion doped region of formation n type in said dark dopant well; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
5 to 8 pairs of formation p-LDMOS transistor technologies of the present invention specify with reference to the accompanying drawings.At first with reference to Fig. 5, Semiconductor substrate 301 is provided, is formed with the dark dopant well 303 of p type in the said Semiconductor substrate, ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well.Before forming said dark dopant well 303, also comprise forming dark n type dopant well 302 steps, said dark n type dopant well 302 degree of depth are greater than dark dopant well.
Said Semiconductor substrate 301 adopts p type silicon usually; Since form said dark dopant well purpose for between the semiconductor device on the Semiconductor substrate and and Semiconductor substrate between isolate; In dark dopant well, forming semiconductor device then, therefore generally at first forming dark n type dopant well 302 so that and form PN junction between the Semiconductor substrate and isolate.
Simultaneously, the structure of dark dopant well can also comprise multiple, is not limited to the structure of illustrated dark dopant well in the present embodiment, such as being structures such as triple-well, the trap that falls back.
The concrete technology that forms dark n type dopant well 302 does, forms said dark n type dopant well 302 and injects through ion and form, and the ion of injection is a phosphonium ion, and the injection energy range is 2000Ke to 2500KeV, and the dosage range of injection is 1E13 to 2E13/cm
2, the angular range of injection is 0 to 7 °.
The concrete technology that forms the dark dopant well 303 of p type does, the dark dopant well 303 that forms said p type injects through ion and forms, and the ion of injection is the boron ion, and the injection energy range is 400KeV to 450KeV, and the dosage range of injection is 1.5E13/cm
2To 2.0E13/cm
2, the angular range of injection is 0 to 7 °.
Then, the dark dopant well 303 that forms said p type comprises that also annealing steps, said annealing temperature are 800 to 1100 ℃ afterwards, and annealing atmosphere is N
2, annealing time is 1 to 3 hour, annealing way is common boiler tube annealing.
As an embodiment, after forming said dark dopant well 303, adopt common boiler tube annealing, annealing temperature is 1000 ℃, annealing atmosphere is N
2, annealing time is 2 hours, air pressure is 1 atmospheric pressure in the time of annealing.
The present technique scheme is passed through after forming dark dopant well at 800 to 1100 ℃ of temperature, N
2Annealing is 1 to 3 hour under the atmosphere, can make the ion distribution of injection repair the damage that the ion injection is caused more evenly, simultaneously.
In dark n type dopant well 302, form the dark dopant well 303 of p type among the present invention; Its conduction type is identical with the channel type of ldmos transistor to be formed in this zone; Purpose is for shortening the raceway groove of ldmos transistor; Strengthen the width of depletion region simultaneously, help to improve the voltage endurance capability of ldmos transistor, this advantage can be found out below.
Then, in the dark dopant well 303 of said p type, form isolation structure 304, said isolation structure 304 is between the source electrode of ldmos transistor to be formed and drain electrode and near drain electrode.Said isolation structure 304 adopts an oxidation (FOX), selective oxidation (LOCOS) or shallow trench isolation to form from (STI) usually, and the employing shallow trench isolation of here relatively optimizing is from (STI) structure.Effect form isolation structure near drain electrode end is similarly the puncture voltage that improves ldmos transistor.
The defective that after forming isolation structure 304, need anneal usually and in forming the isolation structure process, produce to repair; Therefore under the prerequisite of the performance that does not influence semiconductor device; Above-mentioned annealing steps after the dark dopant well 303 that forms said p type carries out after can also staying and forming isolation structure 304 simultaneously; Be the annealing afterwards of shared formation isolation structure 304, its annealing process is same as described above, is not described in detail in this.
With reference to Fig. 6, in the dark dopant well 303 of said p type, form first ion doped region 305 of p type; The degree of depth of said first ion doped region 305 is greater than the isolation structure bottom; And the subregion that covers drain electrode and cover peripheral profile correspondence in said dark dopant well of isolation structure 304 at least.The coverage of first ion doped region 305 is according to the threshold voltage of pipe; Opening resistor (Rdson) or the like is chosen, such as first ion doped region 305 can cover drain electrode and the peripheral profile of isolation structure 304 in said dark dopant well corresponding whole zone, or the peripheral profile that covers drain electrode and isolation structure 304 in said dark dopant well corresponding subregion in addition can cover drain electrode and exceed isolation structure 304 peripheral profile correspondence in said dark dopant well whole zone and to source electrode direction extension.
The doping content of first ion doped region 305 of said p type is greater than the doping content of the dark doping 303 of p type.
Said first ion doped region 305 injects through ion and forms, comparative optimization be that the p type dopant well that said ion injects with voltage device carries out simultaneously.Such as the mask of the p type dopant well of mask that adopt to form first ion doped region 305 simultaneously and middle voltage device, can avoid in the prior art injection process of extra increase like this in order to form the drift region, reduced the technology cost.
More preferably, the mask pattern of the ion of said first ion doped region 305 of formation of the present invention mask pattern that injects and the p type dopant well that forms voltage device is positioned on the same mask.Compare with the extra increase mask of the needs of prior art, can reduce technology cost and the cycle period that reduces product greatly, and can carry out simultaneously with the dopant well in voltage device zone in the formation through the mask that adopts the p type dopant well of voltage device in the formation.Because well-known, in semiconductor technology, the expense of making mask is normally high, and time-consuming.And prior art since the process conditions that form the drift region with form in the condition of dopant well in voltage device zone have big difference and can't with form in the p type dopant well of voltage device inject simultaneously.
The ion of said injection can be the boron ion, injects energy range and be 25 to 280KeV, and the dosage range of injection is 1.4E12 to 2E13/cm
2
As an embodiment, form said first ion doped region 305 and inject formation through ion, the ion of injection can be the boron ion, and the injection energy is 100KeV, and the dosage of injection is 6E12/cm
2
Then, in the dark dopant well 303 of said p type, form second ion doped region 306 of n type; The subregion that said second ion doped region 306 covers the source electrode of ldmos transistor to be formed and covers gate dielectric layer correspondence in said dark dopant well 303 of ldmos transistor to be formed at least; Have between said second ion doped region 306 and first ion doped region 305 at interval.The coverage of said second ion doped region 306 is chosen based on ldmos transistor basic parameter to be formed, such as threshold voltage, and opening resistor (Rdson) or the like.
The doping content of second ion doped region 306 of said n type is greater than the doping content of the dark doping 303 of p type, and the doping content of first ion doped region 305 and second ion doped region 306 is basic identical.
Forming said second ion doped region 306 adopts ion to inject formation; Relatively optimize be the mask pattern that forms said second ion doped region 306 with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask; Promptly can inject formation simultaneously with the n type dopant well of middle voltage device; Compare with the extra increase mask of the needs of prior art; Can reduce technology cost and the cycle period that reduces product greatly through the mask that adopts the n type dopant well of voltage device in the formation, and can carry out simultaneously with the dopant well in voltage device zone in the formation.Because well-known, in semiconductor technology, the expense of making mask is normally high, and time-consuming.And prior art since the process conditions that form the drift region with form in the condition of dopant well in voltage device zone have big difference and can't with form in the n type dopant well of voltage device inject simultaneously.
The ion of said injection can be phosphonium ion, injects energy range and be 90 to 440KeV, and the dosage range of injection is 9.5E12 to 1.5E13/cm
2
As an embodiment, form said first ion doped region 305 and inject formation through ion, the ion of injection is a phosphonium ion, and the injection energy is 140KeV, and the dosage of injection is 5.0E12/cm
2
The order of above-mentioned formation first ion doped region 305 and second ion doped region 306 can be put upside down, and should too much not limit protection scope of the present invention at this.
With reference to Fig. 7, the side wall 309 that on Semiconductor substrate 301, forms gate dielectric layer 307 and polysilicon gate 308 and be positioned at polysilicon gate 308 both sides, these structures of said formation are those skilled in the art's known technology, do not add detailed description at this.Said gate dielectric layer 307 extends to isolation structure
With reference to Fig. 8, form source electrode 310, drain electrode 311 in the dark dopant well 303 of the p type in Semiconductor substrate 301.Said source electrode 310 is positioned at second ion doped region 306 of n type, and said drain electrode 311 is positioned at first ion doped region 305 of p type.Said source electrode 310 and drain electrode 311 specifically also comprise source electrode extension area, the drain electrode extension areas of formation, form said source electrode extension area, the drain electrode extension area is a technology as well known to those skilled in the art, does not add detailed description at this.
Through above-mentioned technology, form p-LDMOS transistor of the present invention, with reference to Fig. 8, comprising: the source electrode 310, drain electrode 311 and the gate dielectric layer 307 that are positioned at Semiconductor substrate 301; Isolation structure 304 is at source electrode 310 with drain between 311 and near drain electrode 311; First ion doped region 305 is positioned at said Semiconductor substrate 301, and the conduction type of said first ion doped region 305 is identical with the conduction type of the raceway groove of ldmos transistor, is the p type; The degree of depth of said first ion doped region 305 is greater than isolation structure bottom and the subregion that covers drain electrode 311 and cover peripheral profile correspondence said Semiconductor substrate 301 in of isolation structure 304 at least; Second ion doped region 306 is positioned at said Semiconductor substrate 301, and the conductivity type opposite of the conduction type of said second ion doped region 306 and the raceway groove of ldmos transistor is the n type; Said second ion doped region 306 covers the source electrodes 310 and the subregion of covering gate dielectric layer 307 correspondence said Semiconductor substrate 301 at least; Have between said second ion doped region 306 and first ion doped region 305 at interval; Also comprise: dark dopant well 303; The conduction type of said dark dopant well 303 is identical with the conduction type of the raceway groove of ldmos transistor; Be the p type, said dark dopant well 303 covers the zone of said first ion doped region 305, second ion doped region 306 and gate dielectric layer 307 correspondence said Semiconductor substrate 301 in.
In the p-LDMOS of above-mentioned technology and formation thereof transistor; In Semiconductor substrate 301, form the p doped deep well 303 identical with the transistorized channel type of p-LDMOS to be formed; Form first ion doped region 305 and second ion doped region 306 of isolating each other in p doped deep well 303 then, said first ion doped region 305 is identical with the transistorized channel type of p-LDMOS, and second ion doped region 306 is opposite with channel type; Therefore the transistorized raceway groove of p-LDMOS that forms is the second ion doped region part of gate dielectric layer 307 correspondences; Therefore compared with prior art raceway groove is shorter, under grid voltage, forms back-biased diode between the dark dopant well 303 of p type and first ion doped region 305 and second ion doped region 306; This depletion region exhausts entirely before puncturing; Can obtain higher puncture voltage, promptly the snap back phenomenon in the I-V curve of ldmos transistor moves to right, and improves the withstand voltage degree of ldmos transistor; Simultaneously, the doping content of first ion doped region 305 through increasing the p type among the present invention can reduce the opening resistor (Rdson) of ldmos transistor; And; Because first ion doped region 305 of the p type that forms is identical with the conduction type of the dark dopant well 303 of p type; Even because when forming first ion doped region 305; Mask in the photoetching process has deviation, when not surrounding isolation structure 304 fully even not surrounding isolation structure 304 parts such as first ion doped region 305, and the too high and actual situation about using of influence of the threshold value that can not cause prior art.
Simultaneously; Mask pattern through will forming said first ion doped region 305 with form in the mask pattern of p type dopant well of voltage device be arranged on the same mask; The mask pattern that forms said second ion doped region 306 with form in the mask pattern of n type dopant well of voltage device be arranged on the same mask, can reduce technology cost and the cycle period that reduces product greatly.
Fig. 9 adopts the transistorized output characteristic curve of p-LDMOS shown in Figure 2 of the prior art; Abscissa is drain voltage (Vd); Ordinate is drain current (Id), and the Medici software of this (Synopsys) company of the snop of this The data U.S. is simulated acquisition.The implantation dosage in the P-zone 204 of the ldmos transistor that wherein, curve I～III is corresponding (i.e. the drift region of drain electrode) successively decreases 25% successively.All the other conditions are identical; On behalf of the condition of the p type dopant well of voltage device in regional 204 employings of the P-of ldmos transistor, curve IV inject, and all the other process conditions of four pipes are all identical among Fig. 9, and threshold voltage is-1.1V; Through simulation; The puncture voltage of the ldmos transistor of curve I～IV representative is respectively-22.5 ,-25.0 ,-27.0 ,-19.4V, drain saturation current Ids is respectively-41 ,-40 ,-38 ,-67 μ A/ μ m, can be found out by the characteristic of I～III curve; Along with reducing of implantation dosage, the puncture voltage of the ldmos transistor of formation reduces.
Figure 10 is the transistorized I-V characteristic curve of p-LDMOS that adopts method of the present invention to form.Ordinate is drain voltage (Vd), and abscissa is drain current (Id), and the Medici software of this (Synopsys) company of the snop of this The data U.S. is simulated acquisition.The dark n type dopant well of the ldmos transistor that wherein, curve I～II is corresponding is different with the implantation dosage of the dark dopant well of p type.The dark n type dopant well implantation dosage of curve I is 1E13, and the injection ion is a phosphorus; The implantation dosage of the dark dopant well of p type is 1.3E13, and the injection ion is a boron.The dark n type dopant well implantation dosage of curve II is 1.5E13, and the injection ion is a phosphorus; The implantation dosage of the dark dopant well of p type is 2.0E13, and the injection ion is a boron.Other technologies of the ldmos transistor that forms are all identical; Threshold voltage is-1.8V, through simulation, the puncture voltage of the ldmos transistor of curve I～II representative is respectively-28 ,-23V; Drain saturation current Ids is respectively-46 ,-47 μ A/ μ m; Characteristic by I～II curve can find out that along with the increase of implantation dosage, the puncture voltage of the ldmos transistor of formation reduces.
Simultaneously; Can analogize; When adopting method of the present invention to make threshold voltage be-during the manufacturing ldmos transistor of 1.1V; Owing to can reduce the concentration of dopant well, so its puncture voltage can be-pipe of 1.8V higher that this explains that method of the present invention has certain advantage for the voltage endurance capability of raising ldmos transistor than threshold voltage.
The present invention gives the transistorized formation method of a kind of n-LDMOS; With reference to Figure 11; Comprise: execution in step S201; Semiconductor substrate is provided, is formed with the dark dopant well of n type in the said Semiconductor substrate, ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; Execution in step S203 forms isolation structure in said dark dopant well, said isolation structure is between source electrode and drain electrode and near drain electrode; Execution in step S205 forms n type first ion doped region in said dark dopant well; The degree of depth of said first ion doped region is greater than the isolation structure bottom; And the subregion that covers drain electrode and cover peripheral profile correspondence in said dark dopant well of isolation structure at least; Execution in step S207, second ion doped region of formation p type in said dark dopant well; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
12 to 15 pairs of formation n-LDMOS transistor technologies of the present invention specify with reference to the accompanying drawings; At first with reference to Figure 12; Semiconductor substrate 401 is provided; Be formed with the dark dopant well 402 of n type in the said Semiconductor substrate, 402 ldmos transistors to be formed have source electrode, drain electrode and gate dielectric layer in said this dark dopant well.
The structure of said dark dopant well can also comprise multiple, is not limited to illustrated dark dopant well structure in the present embodiment, such as being structures such as triple-well, the trap that falls back.
The dark dopant well 402 that forms the n type injects through ion and forms, and specifically technology does, the ion of injection is a phosphonium ion, and the injection energy range is 2000KeV to 2500KeV, and the dosage range of injection is 1E13 to 2E13/cm
2, the angular range of injection is 0 to 7 °.
Then, the dark dopant well 402 that forms said n type comprises that also annealing steps, said annealing temperature are 800 to 1100 ℃ afterwards, and annealing atmosphere is N
2, annealing time is 1 to 3 hour.
As an embodiment, after forming said dark dopant well 303, adopt common tube furnace mode to anneal, annealing temperature is 1100 ℃, annealing atmosphere is N
2, annealing time is 2 hours, air pressure is 1 atmospheric pressure in the time of annealing.
The present technique scheme is passed through after forming dark dopant well at 800 to 1100 ℃, N
2Annealing is 1 to 3 hour under the atmosphere, makes the ion distribution in it more even, can repair ion simultaneously and inject the damage that is caused.
In Semiconductor substrate 401, form the dark dopant well 402 of n type among the present invention; Its conduction type is identical with the transistorized channel type of n-LDMOS to be formed in this zone; Purpose is for shortening the raceway groove of ldmos transistor; Strengthen the width of depletion region simultaneously, help to improve the voltage endurance capability of ldmos transistor.
Then, in said n doped deep well 402, form isolation structure 403, said isolation structure 403 is between the source electrode of ldmos transistor to be formed and drain electrode and near drain electrode.Said isolation structure 403 adopts an oxidation (FOX), selective oxidation (LOCOS) or shallow trench isolation to form from (STI) usually, and the employing shallow trench isolation of here relatively optimizing is from (STI) structure.Effect form isolation structure near drain electrode end is similarly the puncture voltage that improves ldmos transistor.
After forming isolation structure 403, need anneal usually; To eliminate the defective that in forming isolation structure 403 processes, produces; Under the prerequisite of the performance that does not influence semiconductor device, above-mentioned annealing steps after the dark dopant well 402 that forms said n type carries out after can also staying and forming isolation structure 403 simultaneously, the annealing after the promptly shared formation isolation structure 403; Its annealing process is same as described above, is not described in detail in this.
With reference to Figure 13, in said n doped deep well 402, form first ion doped region 404 of n type; The degree of depth of said first ion doped region 404 is greater than isolation structure 403 bottoms; And the outer subregion that is trapped among correspondence in the said n doped deep well 402 that covers drain electrode and cover isolation structure 403 at least.The coverage of first ion doped region 404 is chosen according to the threshold voltage of pipe and opening resistor (Rdson) or the like basic parameter, the peripheral profile that can cover drain electrode and isolation structure 403 such as first ion doped region 404 of n type said dark dopant well 402 in corresponding whole zone, or the subregion even can cover that covers peripheral profile correspondence said dark dopant well 402 in of drain electrode and isolation structure 403 drain and exceed isolation structure 403 peripheral profile correspondence in said dark dopant well 402 whole zone and to source electrode direction extension.
The doping content of first ion doped region 404 of said n type is greater than the doping content of the dark doping 402 of n type.
Said first ion doped region 404 injects through ion and forms, comparative optimization be that n type dopant well with middle voltage device carries out simultaneously.Such as the mask of the n type dopant well of mask that adopt to form first ion doped region 404 simultaneously and middle voltage device, can avoid in the prior art injection process of extra increase like this in order to form the drift region, reduced the technology cost.
More preferably, the ion of said first ion doped region 404 of formation of the present invention mask pattern that injects and the n type dopant well mask pattern that forms voltage device is positioned on the same mask.Compare with the extra increase mask of the needs of prior art, can reduce technology cost and the cycle period that reduces product greatly, and can carry out simultaneously with the dopant well in voltage device zone in the formation through the mask that adopts the n type dopant well of voltage device in the formation.Because well-known, in semiconductor technology, the expense of making mask is normally high, and time-consuming.And prior art since the process conditions that form the drift region with form in the condition of dopant well in voltage device zone have big difference and can't with form in the p type dopant well of voltage device inject simultaneously.
The ion of said injection can be phosphonium ion, injects energy range and be 90 to 440KeV, and the dosage range of injection is 9.5E12 to 1.5E13/cm
2
As an embodiment, form said first ion doped region 305 and inject formation through ion, the ion of injection is a phosphonium ion, and the injection energy is 140KeV, and the dosage of injection is 5.0E12/cm
2
Then, in the dark dopant well 402 of said n type, form second ion doped region 405 of p type; The subregion that said second ion doped region 405 covers the source electrode of ldmos transistor to be formed and covers gate dielectric layer correspondence in said dark dopant well 402 of ldmos transistor to be formed at least; Have between said second ion doped region 405 and first ion doped region 404 at interval.The coverage of said second ion doped region 405 is chosen based on ldmos transistor basic parameter to be formed, such as threshold voltage or the like.
The doping content of second ion doped region 306 of said p type is greater than the doping content of the dark doping 402 of n type, and the doping content of first ion doped region 404 and second ion doped region 405 is basic identical.
Forming said second ion doped region 405 adopts ion to inject formation; The mask pattern that forms said second ion doped region 405 with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask; Promptly can inject formation simultaneously with the p type dopant well of middle voltage device; Compare with the extra increase mask of the needs of prior art; Can reduce technology cost and the cycle period that reduces product greatly through the mask that adopts the p type dopant well of voltage device in the formation, and can carry out simultaneously with the dopant well in voltage device zone in the formation.Because well-known, in semiconductor technology, the expense of making mask is normally high, and time-consuming.And prior art since the process conditions that form the drift region with form in the condition of dopant well in voltage device zone have big difference and can't with form in the p type dopant well of voltage device inject simultaneously.
The ion of said injection can be the boron ion, injects energy range and be 25 to 280KeV, and the dosage range of injection is 1.4E12 to 2E13/cm
2
As an embodiment, form said first ion doped region 404 and inject formation through ion, the ion of injection is the boron ion, and the injection energy is 100KeV, and the dosage of injection is 6E12/cm
2
The order of above-mentioned formation first ion doped region 404 and second ion doped region 405 can be put upside down, and should too much not limit protection scope of the present invention at this.
With reference to Figure 14, the side wall 408 that on Semiconductor substrate 401, forms gate dielectric layer 406 and polysilicon gate 407 and be positioned at polysilicon gate 407 both sides, these structures of said formation are those skilled in the art's known technology, do not add detailed description at this.Said gate dielectric layer 406 extends to isolation structure.
With reference to Figure 15, form source electrode 409, drain electrode 410 in the n doped deep well 402 in Semiconductor substrate 401.Said source electrode 409 is positioned at second ion doped region 405 of p type, and said drain electrode 410 is positioned at first ion doped region 402 of n type.Said source electrode 409 specifically also comprises the source electrode extension area of formation, the extension area that drains with drain electrode 410, owing to be not emphasis of the present invention, does not add detailed description.
Through above-mentioned technology, form ldmos transistor of the present invention, with reference to Figure 15, comprising: the source electrode 409, drain electrode 410 and the gate dielectric layer 406 that are positioned at Semiconductor substrate 401; Isolation structure 403 is at source electrode 409 with drain between 410 and near drain electrode 410; First ion doped region 404 is positioned at said Semiconductor substrate 401, and the conduction type of said first ion doped region 404 is identical with the conduction type of the raceway groove of ldmos transistor, is the n type; The degree of depth of said first ion doped region 404 is greater than isolation structure bottom and the subregion that covers drain electrode 410 and cover peripheral profile correspondence said Semiconductor substrate 401 in of isolation structure 403 at least; Second ion doped region 405 is positioned at said Semiconductor substrate 401, and the conductivity type opposite of the conduction type of said second ion doped region 405 and the raceway groove of ldmos transistor is the p type; Said second ion doped region 405 covers the source electrodes 409 and the subregion of covering gate dielectric layer 406 correspondence said Semiconductor substrate 401 at least; Have between said second ion doped region 405 and first ion doped region 404 at interval; Also comprise: dark dopant well 402; The conduction type of said dark dopant well 402 is identical with the conduction type of the raceway groove of ldmos transistor; Be the n type, said dark dopant well 402 covers the zone of said first ion doped region 404, second ion doped region 405 and gate dielectric layer 406 correspondence said Semiconductor substrate 401 in.
In the n-LDMOS of above-mentioned technology and formation thereof transistor; In Semiconductor substrate 401, form the n doped deep well 402 identical with the transistorized channel type of n-LDMOS to be formed; Form n type first ion doped region 404 and p type second ion doped region 405 of isolating each other in n doped deep well 402 then; Said first ion doped region 404 is identical with the transistorized channel type of n-LDMOS; Second ion doped region 405 is opposite with channel type, and the transistorized raceway groove of n-LDMOS that therefore forms is second ion doped region, 405 parts of gate dielectric layer 406 correspondences, and therefore compared with prior art raceway groove is shorter; Under grid voltage; Form back-biased diode between first ion doped region 404 of the dark dopant well 402 of n type and n type and second ion doped region 405 of p type, this depletion region exhausts entirely before puncturing, and can obtain higher puncture voltage; Be that snap back phenomenon in the transistorized I-V curve of n-LDMOS moves to right, improve the transistorized withstand voltage degree of n-LDMOS; Simultaneously, the doping content of first ion doped region 404 through increasing the n type among the present invention can reduce the transistorized opening resistor of n-LDMOS (rdson); And; Because first ion doped region 404 of the n type that forms is identical with the conduction type of the dark dopant well 402 of n type; Even because when forming first ion doped region 404; Mask in the photoetching process has deviation, when not surrounding isolation structure 403 fully even not surrounding isolation structure 403 parts such as first ion doped region 404, and the too high and actual situation about using of influence of the threshold value that can not cause prior art.
Simultaneously; Mask pattern through will forming said first ion doped region 404 with form in the mask pattern of n type dopant well of voltage device be arranged on the same mask; The mask pattern that forms said second ion doped region 405 with form in the mask pattern of p type dopant well of voltage device be arranged on the same mask, can reduce technology cost and the cycle period that reduces product greatly.
Figure 16 is the transistorized output characteristic curve of n-LDMOS that adopts similar p-LDMOS transistor arrangement shown in Figure 2 in the prior art; Only be the conductivity type opposite in each district with Fig. 2 difference, become p type semiconductor substrate, N-zone 203 such as dark n type dopant well 201 and become p type, P-zone 204 and become n type, source electrode 208 and drain and 209 be N
+
Abscissa is drain voltage (Vd) among Figure 16, and ordinate is drain current (Id), and the Medici software of this (Synopsys) company of the snop of this The data U.S. is simulated acquisition.The implantation dosage in the transistorized n-of the n-LDMOS that wherein, curve I～III is corresponding zone 204 (i.e. the drift regions of drain electrode) successively decreases 25% successively.All the other conditions are identical; On behalf of the condition of the n type dopant well of voltage device in the transistorized n-of n-LDMOS zone 204 employings, curve IV inject; All the other conditions are all identical, and the transistorized threshold voltage of n-LDMOS of four curve representatives is 1.0V, through simulation; The transistorized puncture voltage of n-LDMOS of curve I～IV representative is respectively 22.3,23.0,26.5,19.2V; Drain saturation current Ids is respectively 165,160,150,229 μ A/ μ m, can find out that by the characteristic of I～IV curve along with the reducing of implantation dosage, the puncture voltage of the ldmos transistor of formation reduces.
Figure 17 is the transistorized I-V characteristic curve of n-LDMOS that adopts method of the present invention to form.Abscissa is drain voltage (Vd), and ordinate is drain current (Id), and the Medici software of this (Synopsys) company of the snop of this The data U.S. is simulated acquisition.The dark n type dopant well of the ldmos transistor that wherein, curve I～II is corresponding is different with the implantation dosage of the dark dopant well of p type.The technology of curve I is 1.0e13/cm
2, the technology of curve II is 1.5e13/cm
2Other technologies of the ldmos transistor that forms are all identical; Threshold voltage is 0.7V, and through simulation, the puncture voltage of the ldmos transistor of curve I～II representative is respectively 28,26V; Drain saturation current Ids is respectively 203,253 μ A/ μ m; Characteristic by I～II curve can be found out the increase along with implantation dosage, and the puncture voltage of the ldmos transistor of formation reduces, the corresponding increase of the saturation current that obtains.
Simultaneously, can analogize, when adopting the n-LDMOS transistor of method manufacturing of the present invention and threshold voltage identical (1.0V) among Figure 16; Its puncture voltage can reduce because improving the concentration of dopant well a little; But it still is the same order of magnitude, can not influence actual use, and because it adopts the mask in middle voltage device zone; For reducing cost, this defective is negligible.
The present invention also provides a kind of manufacturing approach that has the semiconductor device of ldmos transistor, comprising: Semiconductor substrate is provided, and said Semiconductor substrate contains high tension apparatus zone (HV) and middle voltage device zone (MV); In the Semiconductor substrate in said high tension apparatus zone, form dark dopant well; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well; In said dark dopant well, form isolation structure, said isolation structure is between source electrode and drain electrode and near drain electrode; In said dark dopant well, form first ion doped region, the conduction type of said first ion doped region is identical with the channel type of said ldmos transistor; The degree of depth of said first ion doped region is greater than the isolation structure bottom; And the subregion that covers drain electrode and cover peripheral profile correspondence in said dark dopant well of isolation structure at least; In said dark dopant well, form second ion doped region, the conduction type of said second ion doped region is opposite with the channel type of said ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
The formation that Figure 18 provides one embodiment of the present of invention has the structural representation of the semiconductor device of ldmos transistor.Comprise:
The i zone of said high tension apparatus zone HV also is formed with dark dopant well 3a and 3b respectively with the ii zone, and said dark dopant well 3a is the p type, and dark dopant well 3b is the n type, and is identical with the channel type of ldmos transistor of formation in the zone separately respectively; The i of voltage device zone MV zone also is formed with dark dopant well 3c and 3d respectively with the ii zone in said, and said dark dopant well 3c is the n type, and said dark dopant well 3d is the p type, respectively with zone separately in the channel type of MOS transistor of formation opposite;
I zone at HV also is formed with isolation structure 4a, and said isolation structure 4a is between the source electrode of ldmos transistor to be formed and drain electrode and near drain electrode; Ii zone at HV also is formed with isolation structure 4b, and said isolation structure 4b is between the source electrode of ldmos transistor to be formed and drain electrode and near drain electrode;
In the dark dopant well 3a in the i of HV zone, also be formed with the first ion doped region 5a; The said first ion doped region 5a is identical with the channel type of ldmos transistor to be formed; Therefore be the p type; The degree of depth of the said first ion doped region 5a is greater than isolation structure 4a bottom, and the subregion that covers the drain electrode of ldmos transistor to be formed and cover peripheral profile correspondence in said dark dopant well 3a of isolation structure at least; Also be formed with the first ion doped region 5b at the ii of HV; The said first ion doped region 5b is identical with the channel type of ldmos transistor to be formed; Therefore be the n type; The degree of depth of the said first ion doped region 5b is greater than isolation structure 4a bottom, and the subregion that covers the drain electrode of ldmos transistor to be formed and cover peripheral profile correspondence in said dark dopant well 3b of isolation structure at least;
In the dark dopant well 3a in the i of HV zone, also be formed with the second ion doped region 6a; The conduction type of the said second ion doped region 6a is opposite with the channel type of said ldmos transistor; Therefore be the n type; The said second ion doped region 6a covers the source electrode of ldmos transistor to be formed and covering gate dielectric layer corresponding subregion in said dark dopant well at least, has between the said second ion doped region 6a and the first ion doped region 5a at interval; In the dark dopant well 3b in the ii of HV zone, also be formed with the second ion doped region 6b; The conduction type of the said second ion doped region 6b is opposite with the channel type of said ldmos transistor; Therefore be the p type; The said second ion doped region 6b covers the source electrode of ldmos transistor to be formed and covering gate dielectric layer corresponding subregion in said dark dopant well at least, has between the said second ion doped region 6b and the first ion doped region 5b at interval;
Be formed with gate dielectric layer 7a, 7b, 7c and 7d respectively on the i of said Semiconductor substrate 1, ii, iii, the iv zone, said gate dielectric layer 7a, 7b, 7c and 7d are in HV zone and can be different at the thickness of MV;
On gate dielectric layer 7a, 7b, 7c and 7d, be formed with polysilicon gate 8a, 8b, 8c, 8d respectively, and the side wall 9a, 9b, 9c, the 9d that are formed at each polysilicon gate both sides respectively.
Be formed with source electrode 10a, 10b and drain electrode 11a, 11b in the i of said Semiconductor substrate 1, ii, iii, the iv zone respectively; Said source electrode 10a, 10b lay respectively in the second ion doping trap 6a, 6b in i, ii zone, and said drain electrode 11a, 11b lay respectively in the first ion doping trap 5a, 5b in i, ii zone; Said source electrode 10c, 10d and drain electrode 11c, 11d lay respectively in iii, the dark dopant well 3c in iv zone and the 3d.
Form the said first ion doped region 5a comparative optimization be with form in the dark dopant well 3d in iv zone of voltage device zone MV carry out simultaneously.More preferably, can the mask pattern of the dark dopant well 3d in the iv zone of voltage device zone MV in mask pattern that form the said first ion doped region 5a and the formation be arranged on the same mask.
Form the said first ion doped region 5b comparative optimization be with form in the dark dopant well 3c in iii zone of voltage device zone MV carry out simultaneously.More preferably, the mask pattern of dark dopant well 3c that can the iii of mask pattern that form the said first ion doped region 5b and middle voltage device zone MV is regional is arranged on the same mask.
Form the said second ion doped region 6a comparative optimization be with form in the dark dopant well 3c in iii zone of voltage device zone MV carry out simultaneously.More preferably, the mask pattern of dark dopant well 3c that can the iii of mask pattern that form the said second ion doped region 6a and middle voltage device zone MV is regional is arranged on the same mask.
Form the said second ion doped region 6b comparative optimization be with form in the dark dopant well 3d in iv zone of voltage device zone MV carry out simultaneously.More preferably, the mask pattern of dark dopant well 3d that can the iv of mask pattern that form the said second ion doped region 6b and middle voltage device zone MV is regional is arranged on the same mask.
If Semiconductor substrate 1 is the p type,, the i zone of HV also comprises the step that forms dark n type dopant well 2a before forming dark dopant well 3a,, the iii zone of MV also comprises the step that forms dark n type dopant well 2c before forming dark dopant well 3c.
Form after said dark dopant well 3a, 3b, 3c and 3d and dark n type dopant well 2a, the 2c, also comprise that annealing steps, said annealing temperature are 800 to 1100 ℃, annealing atmosphere is N
2, annealing time is 2 hours.Through this step annealing, can make ion distribution in it more even and repair ion implantation damage.
Equally, the annealing of this step is carried out after can being placed on and forming isolation structure 4a, 4b, and is promptly shared with formation isolation structure annealing steps afterwards.
Remaining forms the method for the above-mentioned semiconductor device that has a ldmos transistor please with reference to above-mentioned formation p-LDMOS and the transistorized method of n-LDMOS.
The above-mentioned semiconductor device of ldmos transistor and forming method thereof that has; Have and aforesaid p-LDMOS and the similar advantage of n-LDMOS transistor; Can improve its voltage endurance capability, and the mask of the formation dopant well in voltage device zone comes first ion doped region of corresponding formation ldmos transistor and the cycle period that second ion doped region can reduce technology cost and product in adopting.
Though oneself discloses the present invention as above with preferred embodiment, the present invention is defined in this.Any those skilled in the art are not breaking away from the spirit and scope of the present invention, all can do various changes and modification, so protection scope of the present invention should be as the criterion with claim institute restricted portion.
Claims (17)
1. the manufacture method of a ldmos transistor comprises the steps:
Semiconductor substrate is provided;
In said Semiconductor substrate, form dark dopant well; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in the said dark dopant well;
In said dark dopant well, form isolation structure, said isolation structure is between source electrode and drain electrode and near drain electrode;
In said dark dopant well, form first ion doped region, the conduction type of said first ion doped region is identical with the channel type of ldmos transistor; The degree of depth of said first ion doped region greater than isolation structure bottom and cover drain electrode and cover isolation structure at least be trapped among subregion corresponding in the said dark dopant well outward;
In said dark dopant well, form second ion doped region, the conduction type of said second ion doped region is opposite with the channel type of ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
2. the manufacture method of ldmos transistor according to claim 1 forms said dark dopant well and comprises that also annealing steps, said annealing temperature are 800 to 1100 ℃ afterwards, and annealing atmosphere is N
2, annealing time is 1 to 3 hour.
3. the manufacture method of ldmos transistor according to claim 1 also comprises: the dopant well that forms the voltage device that is arranged in said semiconductor substrate surface; Said first ion doped region injects through ion and forms, and said ion injects and the dopant well of voltage device carries out simultaneously.
4. the manufacture method of ldmos transistor according to claim 3, the mask pattern that forms the ion mask pattern that injects and the dopant well that forms voltage device of said first ion doped region is positioned on the same mask.
5. the manufacture method of ldmos transistor according to claim 4; The channel type of said ldmos transistor is the n type; The mask pattern that forms said first ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask, said dark dopant well is the n type.
6. the manufacture method of ldmos transistor according to claim 4; The channel type of said ldmos transistor is the p type; The figure that forms said first ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask, said dark dopant well is the p type.
7. the manufacture method of ldmos transistor according to claim 6 also comprised forming dark n type dopant well step before forming said dark dopant well, and the said dark n type dopant well degree of depth is greater than dark dopant well.
8. ldmos transistor comprises:
Be positioned at source electrode, drain electrode and the gate dielectric layer of Semiconductor substrate;
Isolation structure is between source electrode and drain electrode and near drain electrode;
First ion doped region is positioned at said Semiconductor substrate, and the conduction type of said first ion doped region is identical with the conduction type of the raceway groove of ldmos transistor; The degree of depth of said first ion doped region greater than isolation structure bottom and cover drain electrode and cover isolation structure at least be trapped among subregion corresponding in the said Semiconductor substrate outward;
Second ion doped region is positioned at said Semiconductor substrate, the conductivity type opposite of the conduction type of said second ion doped region and the raceway groove of ldmos transistor; Said second ion doped region cover source electrode and
At least covering gate dielectric layer corresponding subregion in said Semiconductor substrate; Have between said second ion doped region and first ion doped region at interval;
It is characterized in that; Also comprise: dark dopant well; The conduction type of said dark dopant well is identical with the conduction type of the raceway groove of ldmos transistor, and covers the subregion of said first ion doped region, second ion doped region and gate dielectric layer correspondence in said Semiconductor substrate.
9. ldmos transistor according to claim 8 also comprises the dark n type dopant well that is positioned at Semiconductor substrate, and the said dark n type dopant well degree of depth is greater than dark dopant well.
10. manufacturing approach with semiconductor device of ldmos transistor comprises:
Semiconductor substrate is provided, and said Semiconductor substrate contains high tension apparatus zone and middle voltage device zone;
In the Semiconductor substrate in high tension apparatus zone, form dark dopant well; The conduction type of said dark dopant well is identical with the channel type of ldmos transistor to be formed in this dark dopant well, and ldmos transistor to be formed has source electrode, drain electrode and gate dielectric layer in said this dark dopant well;
In said dark dopant well, form isolation structure, said isolation structure is between source electrode and drain electrode and near drain electrode;
In said dark dopant well, form first ion doped region, the conduction type of said first ion doped region is identical with the channel type of said ldmos transistor; The degree of depth of said first ion doped region is greater than the isolation structure bottom; And the outer subregion that is trapped among correspondence in the said dark dopant well that covers drain electrode and cover isolation structure at least;
In said dark dopant well, form second ion doped region, the conduction type of said second ion doped region is opposite with the channel type of said ldmos transistor; Said second ion doped region covers source electrode and covering gate dielectric layer corresponding subregion in said dark dopant well at least; Have between said second ion doped region and first ion doped region at interval.
11. the manufacturing approach of semiconductor device according to claim 10 forms said dark dopant well and comprises that also annealing steps, said annealing temperature are 800 to 1100 ℃ afterwards, annealing atmosphere is N
2, annealing time is 1 to 3 hour.
Form 12. the manufacturing approach of semiconductor device according to claim 11, said first ion doped region are injected through ion, said ion injects and the dopant well of voltage device carries out simultaneously.
13. the manufacturing approach of semiconductor device according to claim 12, the mask pattern that forms the ion mask pattern that injects and the dopant well that forms voltage device of said first ion doped region is positioned on the same mask.
14. the manufacturing approach of semiconductor device according to claim 13; The channel type of said ldmos transistor is the n type; The mask pattern that forms said first ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask, said dark dopant well is the n type.
15. the manufacturing approach of semiconductor device according to claim 13; The channel type of said ldmos transistor is the p type; The figure that forms said first ion doped region with form in the mask pattern of p type dopant well of voltage device be positioned on the same mask; The mask pattern that forms said second ion doped region with form in the mask pattern of n type dopant well of voltage device be positioned on the same mask, said dark dopant well is the p type.
16. the manufacturing approach of semiconductor device according to claim 15 comprised also before forming said dark dopant well forming dark n type dopant well step that the said dark n type dopant well degree of depth is greater than dark dopant well.
17. semiconductor device like claim 10 manufacturing.
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| CN102420245A (en) * | 2010-09-28 | 2012-04-18 | 比亚迪股份有限公司 | Low-voltage trigger silicon controlled rectifier for ESD (Electro-Static Discharge) protection and manufacturing method of low-voltage trigger silicon controlled rectifier |
| CN102157384B (en) * | 2011-03-10 | 2016-08-17 | 上海华虹宏力半导体制造有限公司 | The manufacture method of transistor |
| CN102983161B (en) * | 2011-09-02 | 2015-04-08 | 上海华虹宏力半导体制造有限公司 | Non-buried layer double deep N well high-voltage isolation N-type LDMOS and method for manufacturing N-type LDMOS devices |
| CN103021852B (en) * | 2011-09-22 | 2015-06-03 | 上海华虹宏力半导体制造有限公司 | Method for manufacturing high-voltage P type LDMOS |
| CN103050528A (en) * | 2011-10-17 | 2013-04-17 | 中芯国际集成电路制造(上海)有限公司 | LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistor and manufacturing method thereof |
| CN103730419B (en) * | 2012-10-12 | 2016-04-06 | 北大方正集团有限公司 | A kind of threshold voltage adjustment method |
| CN104157571B (en) * | 2013-05-15 | 2017-03-01 | 中芯国际集成电路制造(上海)有限公司 | The preparation method of LDNMOS pipe |
| CN104282667B (en) * | 2014-09-30 | 2017-11-10 | 中航（重庆）微电子有限公司 | A kind of MOS electrostatic preventing structures and guard method |
| CN104992977B (en) | 2015-05-25 | 2018-06-19 | 上海华虹宏力半导体制造有限公司 | NLDMOS device and its manufacturing method |
| FR3080948A1 (en) * | 2018-05-02 | 2019-11-08 | Stmicroelectronics (Rousset) Sas | INTEGRATED CIRCUIT COMPRISING A CAPACITIVE ELEMENT, AND MANUFACTURING METHOD |
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