Semiconductor Structure and its Fabricating Method
20220037481 · 2022-02-03
Assignee
Inventors
Cpc classification
H01L29/41766
ELECTRICITY
H01L27/088
ELECTRICITY
H01L21/8234
ELECTRICITY
H10B99/00
ELECTRICITY
H01L29/4236
ELECTRICITY
H01L22/12
ELECTRICITY
H01L29/66621
ELECTRICITY
International classification
H01L29/40
ELECTRICITY
H01L29/417
ELECTRICITY
H01L29/423
ELECTRICITY
Abstract
Embodiments of the present application provide a semiconductor structure and its fabricating method, and a semiconductor memory. The method of fabricating a semiconductor structure comprises providing a substrate and performing ion implantation on the substrate to form an active area, forming a gate groove on surface of the substrate, measuring depth of the gate groove, and performing ion implantation compensation, if the depth of the gate groove meets a preset condition, on the substrate according to the depth of the gate groove, and forming an ion compensation region in the active area at one side of the gate groove.
Claims
1. A method of fabricating a semiconductor structure, comprising: providing a substrate and performing ion implantation on the substrate to form an active area; forming a gate groove on surface of the substrate; measuring depth of the gate groove; and performing ion implantation compensation, if the depth of the gate groove meets a preset condition, on the substrate according to the depth of the gate groove, and forming an ion compensation region in the active area at one side of the gate groove.
2. The method of fabricating a semiconductor structure according to claim 1, wherein the step of forming an ion compensation region in the active area at one side of the gate groove comprises: forming a bitline contact hole in the active area at one side of the gate groove; and performing ion implantation compensation on the substrate through the bitline contact hole, and forming the ion compensation region.
3. The method of fabricating a semiconductor structure according to claim 1, wherein the step of performing ion implantation compensation on the substrate according to the depth of the gate groove comprises: fixing implantation depth of compensation ions according to the depth of the gate groove; fixing implantation energy of the compensation ions according to the implantation depth of the compensation ions; and performing ion implantation compensation on the substrate, and forming the ion compensation region according to the implantation energy of the compensation ions.
4. The method of fabricating a semiconductor structure according to claim 1, wherein the preset condition is that the depth of the gate groove is less than a target depth, and that an absolute value of the difference between the depth of the gate groove and the target depth is greater than a threshold standard deviation; the threshold standard deviation is determined according to a result of statistics about depths of plural gate grooves made with the target depth as a processing parameter.
5. The method of fabricating a semiconductor structure according to claim 4, wherein the step of fixing the threshold standard deviation comprises measuring depths of a plurality of the gate grooves, calculating an average value of the depths of the plurality of gate grooves, and calculating a standard deviation of the depths of the plurality of gate grooves, wherein the standard deviation is the threshold standard deviation.
6. The method of fabricating a semiconductor structure according to claim 2, wherein the step of forming a gate groove on surface of the substrate comprises: forming on surface of the substrate a shallow trench isolation structure separating the active area into plural blocks; and forming the gate groove on surface of the substrate, depth of the gate groove being less than depth of the shallow trench isolation structure.
7. The method of fabricating a semiconductor structure according to claim 6, wherein after measuring the depth of the gate groove are further included the following steps: sequentially forming a gate oxidizing layer and a diffusion barrier layer on surface of the gate groove; filling a wordline in the gate groove; and forming a protective layer on surfaces of the wordline and the substrate.
8. The method of fabricating a semiconductor structure according to claim 7, wherein a method of forming the gate oxidizing layer includes thermal oxidation process or deposition process.
9. The method of fabricating a semiconductor structure according to claim 7, wherein the step of filling a wordline in the gate groove comprises: forming a metal layer on surface of the diffusion barrier layer; and etching back the metal layer, with remaining metal layer serving as the wordline, and an upper surface of the wordline being lower than an upper surface of the substrate.
10. The method of fabricating a semiconductor structure according to claim 7, wherein the step of forming a bitline contact hole in the active area at one side of the gate groove comprises: etching the protective layer to form the bitline contact hole; wherein the bitline contact hole penetrates through the protective layer, and exposes the substrate; the bitline contact hole is located between two adjacent ones of the gate grooves in the same and single active area.
11. A semiconductor structure, comprising: a substrate, a gate groove, and an ion compensation region; and an active area, disposed in the substrate; wherein the ion compensation region is located in the active area at one side of the gate groove whose depth meets a preset condition.
12. The semiconductor structure according to claim 11, further comprising a bitline contact hole, whose vertical projection onto the substrate at least partially overlaps with vertical projection of the ion compensation region onto the substrate.
13. The semiconductor structure according to claim 12, further comprising a shallow trench isolation structure, which is located at surface of the substrate and separates the active area into plural blocks; wherein depth of the gate groove is less than depth of the shallow trench isolation structure.
14. The semiconductor structure according to claim 13, wherein the gate groove is located between two adjacent ones of the shallow trench isolation structures.
15. The semiconductor structure according to claim 13, further comprising: a gate oxidizing layer and a diffusion barrier layer disposed on surface of the gate groove; a wordline disposed in the gate groove; and a protective layer disposed on surfaces of the wordline and the substrate; wherein the bitline contact hole penetrates through the protective layer and exposes the substrate, and the bitline contact hole is located between two adjacent ones of the gate grooves in the same and single active area.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0009] In order to more clearly describe the technical solutions of the exemplary embodiments of the present application, brief introduction is made below to the accompanying drawings that are necessary to describe the embodiments. Apparently, the introduced accompanying drawings are merely the drawings directed to partial embodiments to be described in the present application, rather than the entire drawings. Persons ordinarily skilled in the art may acquire other drawings from these accompanying drawings without spending creative effort in the process.
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DESCRIPTION OF EMBODIMENTS
[0025] The present application will be described in greater detail below with reference to the accompanying drawings and the embodiments. As understandable, the specific embodiments described in this context are merely directed to explain the present application, rather than to restrict the present application. As should be additionally noted, to facilitate description, the accompanying drawings merely show partial structures relevant to the present application, rather than the entire structures.
[0026]
[0027] S110: providing a substrate and performing ion implantation on the substrate to form an active area.
[0028] Exemplarily, as shown in
[0029] S120: forming a gate groove on surface of the substrate.
[0030] In some embodiments, referring to
[0031] Referring to
[0032] S130: measuring depth of the gate groove.
[0033] S140: performing ion implantation compensation, if the depth of the gate groove meets a preset condition, on the substrate according to the depth of the gate groove, and forming an ion compensation region in the active area at one side of the gate groove.
[0034] In some embodiments, as shown in
[0035] Exemplarily,
[0036] In the embodiments of the present application, ion implantation compensation is performed on the substrate 110 according to the depth h of the gate groove 140, and an ion compensation region 150 is formed in the active area 121 at one side of the gate groove 140; as shown in
[0037] In addition,
[0038] S110: providing a substrate and performing ion implantation on the substrate to form an active area.
[0039] S120: forming a gate groove on surface of the substrate.
[0040] S130: measuring depth of the gate groove.
[0041] S141: forming a bitline contact hole in the active area at one side of the gate groove if the depth of the gate groove meets a preset condition.
[0042] S142: performing ion implantation compensation on the substrate through the bitline contact hole to form an ion compensation region.
[0043] In some embodiments,
[0044] Referring to
[0045] Moreover,
[0046] S210: fixing implantation depth of compensation ions according to the depth of the gate groove.
[0047] In some embodiments,
[0048] S220: fixing implantation energy of compensation ions according to the implantation depth of the compensation ions.
[0049] In some embodiments,
[0050] S240: performing ion implantation compensation on the substrate according to the implantation energy of compensation ions to form an ion compensation region.
[0051] Exemplarily, the measured value of the depth of the gate groove is h1, and the implantation energy E1 of the compensation ions can be determined; ion implantation compensation is performed on the substrate with the implantation energy E1 of the compensation ions serving as a processing parameter, so that an ion compensation region is formed in the active area at one side of the gate groove to compensate the threshold voltage.
[0052] Moreover, the implantation dose D of the compensation ions can be inferred from the relation between the threshold voltage or the acceptance rate and the ion implantation dose through a great quantity of experimental data, and then obtained through corresponding computation according to the threshold voltage required to be compensated.
[0053] In addition,
[0054] S110: providing a substrate and performing ion implantation on the substrate to form an active area.
[0055] S120: forming a gate groove on surface of the substrate.
[0056] S130: measuring depth of the gate groove.
[0057] S143: performing ion implantation compensation on the substrate according to the depth of the gate groove, and forming an ion compensation region in the active area at one side of the gate groove, if the depth of the gate groove meets a preset condition and is less than a target depth, and an absolute value of the difference between the depth of the gate groove and the target depth is greater than a threshold standard deviation.
[0058] The threshold standard deviation is determined according to a result of statistics about depths of gate grooves of plural semiconductor structures made with the target depth as a processing parameter.
[0059] In some embodiments, h2 is taken as a processing parameter to fabricate a semiconductor structure, then target depth is h2; due to such factors influencing fabrication as processing equipment and processing environment etc., the depth h of the gate groove of the fabricated semiconductor structure might be greater than the target depth h2 and might as well be less than the target depth h2; when the depth h of the gate groove lies within a certain deviation range relative to the target depth h2, performance of the semiconductor structure will not be affected. A threshold standard deviation is calculated and obtained according to a result of statistics about depths h of gate grooves by measuring the depths h of gate grooves of a plurality of normally performing semiconductor structures. Exemplarily, N number of semiconductor structures normally fabricated with target depth h2 as a processing parameter is selected, depths h1 of gate grooves of the N number of normally performing semiconductor structures are measured and obtained, (1≤i≤N), an average value h.sub.avg and standard deviation s of depths h1 of N number of gate grooves are calculated, the average value h.sub.avg serves as a standard average SH, and the standard deviation s serves as a threshold standard deviation DS.sub.th, in other words, when the absolute value of the difference between the depth h of the gate groove of a semiconductor structure and the standard average value SH lies within the range of the threshold standard deviation DS.sub.th, it is considered that no abnormality occurs in the depth of the gate groove of this semiconductor structure. As should be noted, the method of fixing the standard average value and the threshold standard deviation is merely exemplarily described in the embodiment of the present application, and the present application makes no specific restriction thereto.
[0060] When the depth h of the gate groove is less than the target depth h2, the gate groove is distanced relatively far from the channel modulation doping area 122, there is a risk of reduction in the threshold voltage, and it is required to further ascertain whether the depth h of the gate groove is so small as to affect the threshold voltage of the semiconductor structure; when the absolute value of the difference between the depth h of the gate groove of the semiconductor structure and the standard average value SH is greater than the threshold standard deviation DS.sub.th, this indicates that abnormality occurs in the groove depth of the semiconductor structure, and it is therefore required to perform compensation through implantation of compensation ions.
[0061] Exemplarily,
[0062] In addition,
[0063] S121: forming on surface of the substrate a shallow trench isolation structure separating the active area into plural blocks.
[0064] S122: forming the gate groove on surface of the substrate, depth of the gate groove being less than depth of the shallow trench isolation structure.
[0065] In some embodiments, as shown in
[0066] Additionally,
[0067] after measuring the depth of the gate groove, S310: providing a substrate and performing ion implantation on the substrate to form an active area.
[0068] S320: forming a gate groove on surface of the substrate.
[0069] S330: measuring depth of the gate groove.
[0070] S340: sequentially forming a gate oxidizing layer and a diffusion barrier layer on surface of the gate groove.
[0071] S350: filling a wordline in the gate groove.
[0072] S360: forming a protective layer on surface of the wordline and surface of the substrate.
[0073] S370: etching the protective layer to form the bitline contact hole; wherein the bitline contact hole penetrates through the protective layer, and exposes the substrate; the bitline contact hole is located between two adjacent ones of the gate grooves in the same and single active area.
[0074] Exemplarily,
[0075] Referring to
[0076] Referring to
[0077] S380: performing ion implantation compensation, if the depth of the gate groove meets a preset condition, on the substrate according to the depth of the gate groove, and forming an ion compensation region in the active area at one side of the gate groove.
[0078] Based on the same application conception, an embodiment of the present application further provides a semiconductor structure, which is fabricated via a method of fabricating a semiconductor structure according to any embodiment of the present application, and possesses the corresponding advantageous effects as possessed by the method.
[0079] Another embodiment of the present application provides a semiconductor structure, whose structure is as shown in
[0080] In the embodiment of the present application, ion implantation compensation is performed on the substrate 110 according to the depth h of the gate groove 140, and an ion compensation region 150 is formed in the active area 121 at one side of the gate groove 140; the ion compensation region 150 exerts control function on the density of moveable charges in source and drain areas, so as to make it more difficult for source and drain areas at the two sides of the gate groove 140 to be conducted, thus enhancing the threshold voltage, compensating reduction in threshold voltage caused by an unduly shallow depth h of the gate groove 140, avoiding deterioration of performance of the semiconductor structure caused by variation in the depth h of the gate groove 140, and improving performance of the semiconductor memory.
[0081] In addition, still another embodiment of the present application provides still another semiconductor structure, whose structure is as shown in
[0082] Additionally, referring to
[0083] Based on the same application conception, an embodiment of the present application further provides a semiconductor memory, which comprises a semiconductor structure provided by any embodiment of the present application, and possesses the corresponding functions and advantageous effects as possessed by the semiconductor structure.
[0084]
[0085] The semiconductor memory 200 provided by this embodiment of the present application possesses the advantageous effects possessed by the semiconductor structures 100 recited in the foregoing embodiments, while no repetition is made here.
[0086] The above description is merely directed to preferred embodiments of and technical principles employed by the present application. The present application is not restricted to the specific embodiments described herein, and various apparent variations, readjustments and substitutions makeable by person skilled in the art do not depart from the protection scope of the present application. Accordingly, although the present application is described in greater detail with reference to the aforementioned embodiments, the present application is not restricted to the aforementioned embodiments, as other equivalently effective embodiments not departing from the conception of the present application are also included, and the scope of the present application is decided by the scope of the appended claims.