SOI substrate manufacturing method and SOI substrate
10804137 ยท 2020-10-13
Assignee
Inventors
Cpc classification
H01L21/76254
ELECTRICITY
International classification
H01L21/762
ELECTRICITY
H01L31/18
ELECTRICITY
H01L33/00
ELECTRICITY
H01L21/311
ELECTRICITY
Abstract
An SOI substrate manufacturing method and an SOI substrate are provided, where the method includes: forming a patterned etch-stop layer in an oxide layer of a first silicon substrate, bonding a surface, having the patterned etch-stop layer (130), of the first silicon substrate with a surface of a second silicon substrate, and peeling off a part of the first silicon substrate to form a patterned SOI substrate.
Claims
1. A silicon on insulator (SOI) substrate manufacturing method, comprising: forming a patterned etch-stop layer in an oxide layer of a first silicon substrate; wherein the patterned etch-stop layer has a consistent pattern throughout the entire patterned etch-stop layer; bonding a surface of the oxide layer of the first silicon substrate with a surface of a second silicon substrate; peeling off a part of the first silicon substrate to form a pattern-buried SOI substrate; forming a patterned mask on the pattern-buried SOI substrate to expose a device forming area in the pattern-buried SOI substrate; etching the device forming area on the pattern-buried SOI substrate through an etch-stop function of the patterned etch-stop layer to obtain a patterned oxide layer on the second silicon substrate, wherein the patterned oxide layer is under the patterned etch-stop layer; and removing the patterned etch-stop layer in the device forming area to make the entire patterned oxide layer expose in the device forming area to the device forming area, wherein the patterned etch-stop layer outside the device forming area remains present in the silicon substrate after the device is formed.
2. The method according to claim 1, wherein the forming a patterned etch-stop layer comprises: forming a first oxide layer on the first silicon substrate.
3. The method according to claim 2, further comprising: growing a second oxide layer on the patterned etch-stop layer.
4. The method according to claim 3, further comprising: performing flattening processing and chemical surface processing on the second oxide layer.
5. The method according to claim 3, wherein the method further comprises: epitaxially growing a III-V compound in the device forming area to form a device structure.
6. The method according to claim 5, wherein the growing a III-V compound comprise: growing a third oxide layer on the second silicon substrate on which the patterned oxide layer has already been obtained, wherein the third oxide layer is grown outside the device forming area; and growing the III-V compound on the patterned oxide layer of the second silicon substrate on which the third oxide layer is already grown, to form the device structure, wherein the grown III-V compound is connected to the second silicon substrate in a pattern of the patterned oxide layer of the second silicon substrate.
7. The method according to claim 5, wherein the III-V compound comprises aluminium phosphide (AlP), gallium phosphide (GaP), indium phosphide (InP), aluminium arsenide (AlAs), gallium arsenide (GaAs), indium arsenide (InAs), aluminium antimonide (AlSb), gallium antimonide (GaSb), indium antimonide (InSb), aluminium nitride (AlN), gallium nitride (GaN), indium nitride (InN), or ternary and quaternary compounds thereof.
8. The method according to claim 5, wherein the III-V compound in the device forming area is grown by means of a molecular beam epitaxy (MBE) technique, a chemical vapor deposition (CVD) technique, an atomic layer deposition (ALD) technique, or a variation technique thereof, to form the device structure.
9. The method according to claim 5, further comprising: performing annealing processing on the patterned-buried SOI substrate in which the device structure is already formed, to reduce a defect caused by epitaxial lateral overgrowth (ELO) of the III-V compound in the device forming area.
10. The method according to claim 2, further comprising: performing ion implantation on the first silicon substrate to form a defect layer in a silicon layer of the first silicon substrate, wherein a peeled-off part of the first silicon substrate comprises the defect layer in the first silicon substrate and a silicon layer on the defect layer.
11. The method according to the claim 2, further comprising: performing low-temperature annealing processing to make abutted surfaces of the first silicon substrate and the second silicon substrate tightly bonded; and performing surface polishing processing on the pattern-buried SOI substrate.
12. The method according to claim 1, wherein the patterned etch-stop layer comprises a material having etching selectivity to the oxide layer of the first silicon substrate.
13. The method according to claim 1, wherein the patterned etch-stop layer comprise a plurality of same patterns, and each patterns has a pattern size that is less than 20 nm, and a thickness of the patterned etch-stop layer is less than 50 nm.
14. The method according to claim 1, wherein the method further comprises: forming a photoelectric device structure in the device structure, wherein the photoelectric device structure comprises a multi-layer structure.
15. An apparatus, comprising: a first silicon substrate; an oxide layer of the first silicon substrate formed on one surface of the first silicon substrate; a patterned etch-stop layer formed in the oxide layer of the first silicon substrate; wherein the patterned etch-stop layer has a consistent pattern throughout the entire patterned etch-stop layer; a second silicon substrate, formed on the oxide layer of the first silicon substrate; a SOI substrate, formed by peeling off a part of the first silicon substrate after bonding a surface of the oxide layer of the first silicon substrate with a surface of a second silicon substrate; a device forming area on the SOI substrate, formed by a first patterned mask on the SOI substrate to expose an area; a patterned oxide layer, formed by etching the device forming area on the SOI substrate through an etch-stop function of the patterned etch-stop layer, wherein the entire patterned oxide layer exposes to the device forming area, and wherein the patterned etch-stop layer outside the device forming area remains present in the silicon substrate after the device is formed; a device structure, formed by epitaxially growing a III-V compound in the device forming area.
16. The apparatus according to claim 15, wherein oxide layer of the first silicon substrate comprises: a first oxide layer, formed on the first silicon substrate; the patterned etch-stop layer, formed on the first oxide layer of the first silicon substrate, and wherein the patterned etch-stop layer is obtained by etching an etch-stop layer according to a patterned mask on the etch-stop layer; and a second oxide layer, grown on the patterned etch-stop layer.
17. The apparatus according to claim 15, wherein the patterned etch-stop layer comprises a material having etching selectivity to the oxide layer of the first silicon substrate.
18. The apparatus according to claim 15, wherein the patterned etch-stop layer comprise a plurality of same patterns, and each patterns has a pattern size that is less than 20 nm, and a thickness of the patterned etch-stop layer is less than 50 nm.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1) The following briefly describes the accompanying drawings required for describing the embodiments or the prior art.
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DESCRIPTION OF EMBODIMENTS
(9) The following describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure.
Embodiment 1
(10)
(11) S110: Form a patterned etch-stop layer in an oxide layer of a first silicon substrate.
(12) Currently, in a structure of a commonly used SOI substrate, an oxide layer is introduced between a top-layer silicon substrate and a bottom-layer silicon substrate. As shown in
(13) It should be noted that, in this embodiment, a pattern size of the patterned etch-stop layer 130 may be less than 20 nm, and a thickness of the patterned etch-stop layer 130 may be less than 50 nm. Similarly, a thickness of an oxide layer above the patterned etch-stop layer 130 may also be less than 50 nm, and oxide layers above and under the patterned etch-stop layer 130 are connected as a whole.
(14) According to a theory proposed by Luryi and Suhir, a stress field vertical to an epitaxial layer on a substrate accords with exponential decay in a growing direction z, as indicated by the following expression (1):
(15)
(16) In the foregoing expression (1), 21 is a lateral dimension of a pattern, and it can be known that the stress field exponentially decays as a pattern size is decreased. Therefore, as long as the pattern is small enough, a critical thickness of an epitaxial layer in which dislocations occur tends to infinity, which is equivalent to that a heteroepitaxial layer without threading dislocations can be formed on a silicon substrate.
(17) According to the SOI substrate manufacturing method provided in this embodiment, the patterned etch-stop layer 130 whose pattern size is extremely small is formed in the oxide layer 120 of the first silicon substrate 110. An SOI substrate manufactured using this method is applicable to growing a material having lattice mismatch with silicon, and a heteroepitaxial layer without threading dislocations can be formed on a silicon substrate.
(18) S120: Bond a surface, having the patterned etch-stop layer, of the first silicon substrate with a silicon surface of a second silicon substrate, and peel off a part of the first silicon substrate to form a patterned SOI substrate.
(19) In this embodiment, the patterned etch-stop layer 130 is already formed in the oxide layer 120 of the first silicon substrate 110, there may be a thin oxide layer on a surface of a second silicon substrate 210, and the oxide layer on the surface of the second silicon substrate 210 may be a natural oxide layer, or may be formed using a thermal oxidation technique. When bonding processing is performed on the first silicon substrate 110 and the second silicon substrate 210, the first silicon substrate 110 may be turned over, so that a surface, having the patterned etch-stop layer 130, of the first silicon substrate 110 is bonded with the surface of the second silicon substrate 210, and then a part of the first silicon substrate 110 is peeled off to obtain a substrate structure in which the oxide layer 120 exists between the first silicon substrate 110 and the second silicon substrate 210, that is, a patterned SOI substrate 300. As shown in
(20) According to the SOI substrate manufacturing method provided in this embodiment, a patterned etch-stop layer is formed in an oxide layer of a first silicon substrate, a surface, having the patterned etch-stop layer, of the first silicon substrate is bonded with a silicon surface of a second silicon substrate, and a part of the first silicon substrate is peeled off to form a patterned SOI substrate. The structure can resolve a problem in the prior art that when a heteroepitaxial layer is grown on a silicon layer of an SOI substrate, a great quantity of threading dislocations is caused in the epitaxial layer due to lattice mismatch and thermal mismatch occurred between the silicon layer and the heteroepitaxial layer. According to the patterned SOI substrate provided in this embodiment, a heteroepitaxial layer without threading dislocations can be formed on a silicon substrate, improving usage performance and reliability of a photoelectric device.
Embodiment 2
(21)
(22) S200: Form a first oxide layer on a first silicon substrate.
(23) Referring to
(24) S210: Perform ion implantation on the first silicon substrate, and form a defect layer in a silicon layer of the first silicon substrate.
(25) Referring to
(26) S220: Form a patterned etch-stop layer on the first oxide layer of the first silicon substrate.
(27) Specifically, for specific implementation of S220, refer to S110 in Embodiment 1.
(28) Optionally, S220 in this embodiment may include: forming an etch-stop layer 130 on the first oxide layer 121 of the first silicon substrate 110, forming a patterned mask on the etch-stop layer 130, and obtaining a patterned etch-stop layer 130 using an etching technique. The patterned mask includes a patterned photoresist obtained using an extreme ultraviolet (EUV) lithography method, and a pattern whose feature size is less than 20 nm may be manufactured using a EUV photolithography technique.
(29) Referring to
(30) It should be noted that, a material of the patterned etch-stop layer 130 is a material having etching selectivity to the first oxide layer 121, and may generally include a material such as silicon nitride, aluminium oxide, titanium oxide, silicon rich silicon oxide, or hydrogen rich silicon nitride, where these materials may have a high etching selective ratio to the first oxide layer 121.
(31) In another possible implementation manner of this embodiment, the patterned mask may also be a porous alumina film; in this implementation manner, the photolithography technology is not required, and the porous alumina film is directly stuck on the etch-stop layer 130 for patterning processing. Similar to the foregoing embodiment, in this embodiment, a pattern size of the patterned mask may be less than 20 nm, and a pattern size of the patterned etch-stop layer 130 may also be less than 20 nm.
(32) S230: Grow a second oxide layer on the patterned etch-stop layer, and perform flattening processing and chemical surface processing on the second oxide layer.
(33) Referring to
(34) It should be noted that, the first oxide layer 121 and the second oxide layer 122 may be made of a silicon oxide material, a thickness of the second oxide layer 122 may be less than 50 nm, film materials of the second oxide layer 122 and the first oxide layer 121 are generally the same, and the second oxide layer 122 is connected to the first oxide layer 121 in a window area 130a of the patterned etch-stop layer 130, so as to form an oxide layer having an integral structure.
(35) S240: Bond a surface, having the patterned etch-stop layer, of the first silicon substrate with a silicon surface of a second silicon substrate, and peel off a part of the first silicon substrate to form a patterned SOI substrate.
(36) Specifically, for specific implementation of the bonding processing in S240, reference may be made to S120 in Embodiment 1.
(37) Referring to
(38) Referring to
(39) S250: Perform low-temperature annealing processing, so that abutted surfaces of the first silicon substrate and the second silicon substrate are tightly bonded.
(40) S260: Perform surface polishing processing on the patterned SOI substrate.
(41) In this embodiment, annealing processing is further performed on the already formed patterned SOI substrate 300, so that abutted surfaces of the two silicon substrates, that is, surfaces of the second oxide layer 122 of the first silicon substrate 110 and the second silicon substrate 210 are tightly bonded. Further, because the silicon layer 110a of the first silicon substrate 110 in the patterned SOI substrate 300 is peeled off, various surface polishing processing may be performed on the patterned SOI substrate 300 after the silicon layer 110a is peeled off, where a smooth surface structure facilitates performing various processing when a device is formed.
(42) According to the SOI substrate manufacturing method provided in this embodiment, a patterned etch-stop layer is formed in an oxide layer of a first silicon substrate, a surface, having the patterned etch-stop layer, of the first silicon substrate is bonded with a silicon surface of a second silicon substrate, and a part of the first silicon substrate is peeled off to form a patterned SOI substrate, which resolves a problem in the prior art that when a heteroepitaxial layer is grown on a silicon layer of an SOI substrate, a great quantity of threading dislocations is caused due to lattice mismatch and thermal mismatch occurred between the silicon layer and the heteroepitaxial layer.
(43) According to the patterned SOI substrate provided in this embodiment, a heteroepitaxial layer without threading dislocations can be formed on a silicon substrate, improving usage performance and reliability of a photoelectric device.
Embodiment 3
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(45) S310: Form a patterned mask on a patterned SOI substrate to expose a device forming area.
(46) Referring to
(47) S320: Etch the device forming area on the patterned SOI substrate to obtain a patterned oxide layer on a second silicon substrate.
(48) Referring to
(49) It should be noted that, materials of the etched silicon layer 110b, first oxide layer 121, and part of the second oxide layer 122 of the first silicon substrate 110 in the device forming area 400 are silicon oxide, and a material of the patterned etch-stop layer 130 may be a material having etching selectivity, and generally includes a material such as silicon nitride, aluminium oxide, titanium oxide, silicon rich silicon oxide, or hydrogen rich silicon nitride. In specific implementation, an etching gas having a high selective ratio to silicon oxide may be selected, thereby implementing that the patterned etch-stop layer 130 is barely etched while the silicon oxide is etched. The etching gas may generally include an addition of a fluorine-based gas having high carbon content, such as C.sub.2F.sub.2 or CHF.sub.3, or hydrogen content in the etching gas may be increased. Therefore, the patterned oxide layer 123 on the second silicon substrate 210 and the patterned etch-stop layer 130 can be formed after silicon oxide is etched, where the patterned oxide layer 123 is the part of the second oxide layer 122, and is specifically a part, covered by the patterned etch stop layer 130, of the second oxide layer 122. Description is made using an example in which the material of the patterned etch-stop layer 130 is silicon nitride. Similarly, an etching gas having a high selective ratio to silicon nitride is selected, so as to implement that the patterned oxide layer 123 is barely etched while the patterned etch-stop layer 130 is etched. Therefore, the patterned oxide layer 123 having a small-size pattern is finally obtained in the device forming area 400 of the patterned SOI substrate 300, where the pattern has a size the same as the pattern size of the patterned etch-stop layer 130 in the foregoing embodiment, and is generally less than 20 nm. It should be further noted that, a lower aperture of a window of the patterned oxide layer 123 that is formed by means of etching is generally less than or equal to an upper aperture of the window, that is, the window has a vertical or sloping side wall.
(50) S330: Epitaxially grow a III-V compound in the device forming area to form a device structure.
(51) Referring to
(52) It should be noted that, the III-V compound in this embodiment may include, for example, AlP, GaP, InP, AlAs, GaAs, InAs, AlSb, GaSb, InSb, MN, GaN, InN, or ternary and quaternary compounds thereof. A manner of epitaxially growing the III-V compound in the device forming area 400 may include, for example, a molecular beam epitaxy (MBE) technique, a chemical vapor deposition (CVD) technique, an atomic layer deposition (ALD) technique, or a variation technique thereof. For example, a variation technique of CVD may include: metal organic chemical vapor deposition (MOCVD), plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD), ultra high vacuum chemical vapor deposition (UHVCVD), and reduced pressure chemical vapor deposition (RPCVD).
(53) According to the method provide in this embodiment, a patterned etch-stop layer is formed in an oxide layer of a first silicon substrate, a surface, having the patterned etch-stop layer, of the first silicon substrate is bonded with a surface of a second silicon substrate, and a part of the first silicon substrate is peeled off to form a patterned SOI substrate; further, an oxide layer having a small-size pattern on the second silicon substrate is formed in a device forming area on the patterned SOI substrate by means of an etch-stop function of the patterned etch-stop layer, and a heteroepitaxial layer without threading dislocations can be grown in the device forming area using this patterned oxide layer on the second silicon substrate, which resolves a problem in the prior art that when a heteroepitaxial layer is grown on a silicon layer of an SOI substrate, a great quantity of threading dislocations is caused due to lattice mismatch and thermal mismatch occurred between the silicon layer and the heteroepitaxial layer, and improves usage performance and reliability of a photoelectric device. Further, according to the method provided in this embodiment, the heteroepitaxial layer without threading dislocations can be grown by performing photolithography in the device forming area only once, improving compatibility with a CMOS technique.
(54) Further, in this embodiment, annealing processing may be further performed on the patterned SOI substrate 300 in which the device structure 170 is already formed, so as to reduce a defect caused in an ELO process of the III-V compound in the device forming area 400.
(55) In this embodiment, the heteroepitaxial layer without threading dislocations is formed in the device forming area 400 of the patterned SOI substrate 300, and therefore, a photoelectric device structure can be formed in the device forming area 400, that is, on the device structure 170, where the photoelectric device structure generally includes a multi-layer structure.
(56) Referring to
(57) Referring to
(58) Referring to
(59) Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solutions of the present disclosure, but not for limiting the present disclosure. Although the present disclosure is described in detail with reference to the foregoing embodiments, persons of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements to some or all technical features thereof, without departing from the scope of the technical solutions of the embodiments of the present disclosure.