EP1935010A2 - Self-organized pin-type nanostructures, and production thereof on silicon - Google Patents
Self-organized pin-type nanostructures, and production thereof on siliconInfo
- Publication number
- EP1935010A2 EP1935010A2 EP06807129A EP06807129A EP1935010A2 EP 1935010 A2 EP1935010 A2 EP 1935010A2 EP 06807129 A EP06807129 A EP 06807129A EP 06807129 A EP06807129 A EP 06807129A EP 1935010 A2 EP1935010 A2 EP 1935010A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- silicon
- structures
- needle
- nanostructure
- plasma
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 80
- 239000010703 silicon Substances 0.000 title claims abstract description 80
- 239000002086 nanomaterial Substances 0.000 title claims description 41
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 238000000034 method Methods 0.000 claims abstract description 108
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 102
- 238000005530 etching Methods 0.000 claims abstract description 37
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- 239000013078 crystal Substances 0.000 claims abstract description 25
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 15
- 229910052760 oxygen Inorganic materials 0.000 claims description 15
- 239000001301 oxygen Substances 0.000 claims description 15
- 238000001020 plasma etching Methods 0.000 claims description 14
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- 239000000463 material Substances 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 5
- 230000001419 dependent effect Effects 0.000 claims description 5
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 4
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- 229910018503 SF6 Inorganic materials 0.000 claims description 2
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
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- 229960000909 sulfur hexafluoride Drugs 0.000 claims description 2
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical group FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims 2
- 238000004140 cleaning Methods 0.000 claims 2
- 229910052799 carbon Inorganic materials 0.000 claims 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims 1
- 239000012535 impurity Substances 0.000 claims 1
- FAQYAMRNWDIXMY-UHFFFAOYSA-N trichloroborane Chemical compound ClB(Cl)Cl FAQYAMRNWDIXMY-UHFFFAOYSA-N 0.000 claims 1
- 235000012431 wafers Nutrition 0.000 abstract description 8
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- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
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- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/3065—Plasma etching; Reactive-ion etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
- H01L21/3083—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
- H01L21/3086—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
- H01L21/32135—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only
- H01L21/32136—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas
- H01L21/32137—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas of silicon-containing layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32139—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer using masks
Definitions
- the invention generally relates to the production of structured silicon surfaces and in particular to the generation of needle-like structures with nano-dimensions in the range, for example, below the wavelengths of visible light, these structures being referred to below as nanostructures.
- silicon is often processed accordingly, which often includes a structuring of the silicon.
- a mask of photoresist is generally produced, with the aid of which the removal is controlled by an etching process, eg WO-A 2005/045941.
- the photoresist In order to produce small structures by means of a resist mask, the photoresist must be exposed with an exposure mask corresponding to small structures. In the range below the usual wavelengths of light that are available for the exposure of the photoresist, this is possible only with increased effort. Often, however, structures with high aspect ratio features are needed, ie, the depth or height of the features is small relative to their lateral dimension.
- All of the enumerated methods have in common that they do not achieve a high aspect ratio of the nanostructures, especially if a low defect density is desired.
- the nanostructure there typically has an increased contamination density and / or an increased number of crystal defects after the production, if at the beginning single crystal silicon with a low crystal defect density was present. Therefore, these known methods can be used only to a limited extent or with worse results with regard to the overall performance of the component.
- microstructuring using self-assembly to produce structured silicon surfaces has also been using plasma-assisted reactive ion methods, also known as RIE methods, based on SF 6 (sulfur hexafluoride) and oxygen, but using metal particles Micro-masking and thus ensured the formation of structure, cf. WO-A 02/13279, US Pat. No. 6,091,021, US Pat. No. 6,329,296.
- plasma-assisted reactive ion methods also known as RIE methods, based on SF 6 (sulfur hexafluoride) and oxygen, but using metal particles Micro-masking and thus ensured the formation of structure, cf. WO-A 02/13279, US Pat. No. 6,091,021, US Pat. No. 6,329,296.
- a major disadvantage of this method is the use of metals in the plasma, which can lead to undesirable contamination of the silicon.
- the harmful effects of least metal traces in the semiconductor manufacturing process, especially in integrated circuits are known.
- the overhead of these processes is also detrimental to use in manufacturing processes that require high yield and low process costs.
- the invention has for its object to provide structures with high aspect ratio and nano-dimensions on silicon surfaces, the cost of a separate masking should be avoided or at least reduced and improved behavior with respect to crystal defects and chemical surface contamination compared to conventional Process is to be achieved and a high degree of compatibility with other manufacturing processes should be possible.
- the object is achieved by a method for producing a structured silicon surface, as described in claim 1.
- a reactive plasma atmosphere having at most two different gas components with oxygen and a reactive gas for etching silicon is produced by setting process parameters which develop a self-masking effect for producing a nanostructure.
- the etching takes place without further working gases and is carried out as a one-step process.
- the silicon surface is exposed to the action of the etching plasma without any further process steps taking place; in particular, no further measures are necessary to achieve a targeted micro-masking of the silicon surface. Nonetheless, practical "freedom from defects" is achieved, in the sense that no defects are supplemented by the reactive plasma.
- Plasma atmosphere resulting needle-like structures to a value of 4 or greater set by controlling the process time.
- a masking of the silicon surface is dispensed with.
- the needle-like structures produced by the method according to the invention have a shape which is best suited for optical applications in the visible light range and also in the infrared range. That is, by the self-organized
- Masking of the etching produced form of the needle-like structures in addition to the aspect ratio of greater than 4 also has a "pyramid-like" shape, with a very tapered needle end is formed, but at the foot of the above needle-like outgoing form a relatively shallow leaking area is generated, which expires shallow.
- the lateral dimensions increase significantly toward the foot.
- Between the circumscribed pyramid-like structures with needle tip remains a clear distance, at least 50 nm, so that in spite of high needle density too close to each other standing needles are prevented. Such too dense needles would converge to a larger entity and bring the etching process to a halt here.
- pyramid-like needles can be exposed to considerable mechanical stresses. At best, they are bent or smeared here, but not destroyed. Mechanical stresses of the following kind do not lead to such a destruction of the mechanical needle structure that disadvantageous consequences arise with respect to the reflection of the nanostructure with the pyramid-like needles:
- a profilometer needle of the profilometer exerts a pressure between 0.1 and 10 mg on the sample to be measured (the nano-surface with the pyramidal needles).
- the Profilometer needle is very pointed, but increases in diameter quickly, so that when moving on a sample a 5 ⁇ m deep well with a width of 1 micron can not be resolved exactly in the measurement image.
- a pressure of typically 5 mg and a movement of the profilometer needle at a rate of up to 100 ⁇ m / sec on the nanostructure no adverse effect on the reflection properties of the nanostructure was observed, as would occur if the pyramidal needle structure were destroyed.
- the (total) reflection is below 0.4% for a wavelength range between 400 nm and about 1000 nm (scattered and direct reflection). In an extended range between 180 nm and 3000 nm, the (total) reflection is below 2% (practically only the scattered reflection). Reflection is a physical property of the nanostructure that is reproducible, measurable, and comparable to another structure.
- the inventors' investigations indicate that efficient self-organized masking (as "self-marking") is achieved by the etching process itself rather than by pre-existing or specially added materials.
- Corresponding investigations on the basis of Auger electron spectroscopy (AES) and energy dispersion X-ray spectroscopy (EDX) indicate that the masking effect is caused by SiO x , so that a high shielding effect is achieved by the locally formed silicon oxide.
- AES Auger electron spectroscopy
- EDX energy dispersion X-ray spectroscopy
- both the number of contamination defects that are caused for example by ⁇ tzneben occur usually, as well as crystal damage, which are found in conventional plasma-based process to reduce significantly or to avoid within the measurement accuracy substantially.
- neither RHEED, CV measurements, TEM or PDS, such defects - as a result of the etching regime of the invention - could be detected.
- the fabricated nanostructure can be provided by a single plasma etch step in a quality that does not require further material removal.
- the structures produced by the method show no edge shading at high edges. It is thus possible, for example, to structure surfaces of a few ⁇ m, even if the surface is surrounded by a 5 ⁇ m high structure.
- the structuring of the silicon is done by the plasma in the RIE process. These structures are deepened by the etching process, resulting in the structures in the nanometer range with enormous aspect ratios.
- the process is performed with a working gas consisting of SF 6 and O 2. This results in the needle-like structures with less
- Defect rate ie, low crystal defect density and low surface contamination, regardless of the crystallographic orientation of the silicon base surface, whereby a high degree of flexibility for the integration of the invention Method is provided in corresponding manufacturing processes for silicon-containing components.
- another working gas combination with O 2 is used as a component.
- carbon fluorides may be used in conjunction with oxygen as the second gas component.
- SF 6 or the other aforementioned reactive gases are in each case next to oxygen, the second of the two gas components and in this case the actual etching gas, whereas O 2 increases the etching rate and causes the self-masking (passivation). It also produces a high selectivity for SiO 2 in the etching behavior, so that an efficient limitation of the silicon surface to be structured by means of a corresponding mask layer is possible.
- the product thus obtained has a low-defect nanostructure surface (claim 27, claim 33, claim 32). It has a height of the free-standing pyramid-like needles over at least 400 nm and a gap of at least 50 nm. The height is between 400 nm and 1000 nm, which is circumscribed by the compression factor of the image of the electron beam micrograph (claim 33).
- the visual stress occurs due to the limited possible structural description of the pyramid-like needles and their environment. For comparison, reference may be made to the John Hancock Center in Chicago, which is about 350m high, slightly pyramid-like, and has a lateral foot measurement (with no shallow, relatively shallow leakage) of about 85m.
- This structure is constructed in a reduced by a factor of 10 9 form in silicon, often side by side and difficult to visualize on this scale with the current imaging techniques and clearly described. On the one hand, this task is not simple, but on the other hand, it is essentially fulfilled by measuring and presenting the effects of these structures.
- the temperature of the first element As described in further embodiments, the temperature of the first element
- the temperature of the silicon surface is set at 27 ° C., preferably in the range ⁇ 5 ° C.
- Adjustment of the other process parameters occurs as the temperature, the typically represents a "sensitive" parameter is given in a very accurate manner.
- Process pressure and plasma power are also suitably matched to each other, as also set out in the dependent claims and set forth in the following description in order to obtain the desired aspect ratio with a simultaneously reduced contamination rate and low crystal defect density.
- the ratio of not more than two working gases is adjusted so that etching removal and self-masking balance each other out. This ensures both the structuring and the required freedom from defects (no additional defects due to the etching regime).
- the absolute parameter values can be efficiently adapted to the proportion of the open (or free) silicon surface. If the Si surface is covered to a high surface area by a mask layer, for example oxide or silicon nitride, this can be compensated for at least by an increase of the reactive gas fraction, for example of the SF 6 fraction, in particular also if the SF 6 fraction is increased. simultaneous reduction of oxygen content and simultaneous increase of process pressure ..
- the preceding object is achieved according to a further aspect by a method having the features of claim 12.
- the method comprises generating a reactive plasma atmosphere with oxygen and a reactive gas consisting of a mixture of HCl and BCI 3 for etching silicon without further process steps by setting process parameters that develop a self-masking effect to produce a nanostructure with needle-like structures , Also in this case, a self-organizing masking effect can be achieved so that the above-described properties (or shapes) of the nanostructures are obtained.
- the object is achieved by a method according to claim 18, in which the production of silicon structures with an aspect ratio of 4 to 1 or greater in a single plasma etching step is described, wherein a self-masking effect based on oxygen and a reactive Gas, e.g. B. SF 6 is achieved and at the same time the defect rate in terms of contamination and crystal defects remains low.
- a reactive Gas e.g. B. SF 6
- a nanostructure comprising a randomly distributed monocrystalline needle-like silicon structure formed on a monocrystalline silicon base layer, the aspect ratio of the needle-like silicon structures being 4 or greater, the crystal defect density being in the silicon structures is not higher than in the silicon base layer (claim 27).
- the nanostructure which thus has silicon structures with lateral dimensions that are typically below the wavelength of visible light, can thus be used efficiently as a layer in devices in which a gradual change in refractive index between silicon and another material is desired. As a result, the reflection behavior and / or the
- Transmission behavior of optoelectronic components can be significantly improved. Furthermore, by the nanostructure a significantly increased surface area can be obtained, for example, to a significantly extended Residence time of substances in the vicinity of the nanostructure compared to substantially planar surfaces leads, which can be advantageously exploited in sensor applications. Due to the crystal defect density, which is the same as in the silicon base layer, the nanostructure can also be used efficiently in applications in which high crystal quality is required for further processing.
- the silicon structures are delimited by a mask layer, wherein the silicon structures are formed up to (very close to) the corresponding edge (edge flank).
- the nanostructure can be used efficiently as a window of an optoelectronic component.
- the mask layer can even have a thickness of several micrometers, about 5 ⁇ m, so that effective passivation layers can be used to expose desired regions of a silicon base layer for the formation of a nanostructure.
- Fig. 1 is an electron micrograph of a RIE etched
- 2 is an electron micrograph with an obliquely incident electron beam, from which the homogeneity of the distribution of the silicon needles and the depth of the spaces between the needles are visible,
- Fig. 3 is a TEM electron micrograph of the tip of a silicon needle in transmission with high resolution.
- Figure 3a is Figure 3 rotated so that [001] is vertical.
- FIG. 4 a is the electron micrograph of FIG. 2 with an obliquely incident electron beam from which the homogeneity of the distribution of the silicon needles and the depth of the interspaces between the needles are visible, here a left-hand section.
- Fig. 4b is the electron micrograph of Figure 2 with obliquely incident electron beam, from which the homogeneity of the distribution of the silicon needles and the depth of the spaces between the needles are visible, here an intermediate section.
- Fig. 4c is the electron micrograph of Fig. 2 with obliquely incident electron beam from which the homogeneity of the distribution of the silicon needles and the depth of the interstices between the needles are visible, here a right portion.
- Fig. 5 is the electron micrograph of Fig. 2 with obliquely incident electron beam from which the homogeneity of the distribution of the silicon needles and the depth of the spaces between the needles are visible, here a front portion.
- Fig. 6 is the electron micrograph of Figure 2 with obliquely incident electron beam, from which the homogeneity of the distribution of the silicon needles and the depth of the spaces between the needles are visible, here completely.
- needle-like silicon structures are to be understood as "pyramid-like" structures having a tip with lateral dimensions of a few nanometers, wherein the tip increases significantly downwards in its lateral dimension, so that in the lower part of the structure a lateral dimension of some ten nanometers or at least 100 nm is achieved.
- the silicon base layer 3 is limited in this embodiment by a mask layer 5, which may be composed of silicon dioxide, silicon nitride or the like, wherein the needle-like silicon structures 4 are formed up to an edge region 5 a of the mask layer 5.
- the mask layer 5 which may be composed of silicon dioxide, silicon nitride or the like
- Silicon base layer 3 is a portion of a 6 inch diameter silicon wafer with a (100) surface orientation that has a p-type doping giving a resistivity of 10 ohm.cm.
- the base layer 3 may have any desired crystal orientation with any predoping.
- the base layer 3 may be formed substantially of amorphous or polycrystalline silicon.
- FIG. 2 shows an enlarged detail of the nanostructure 2, wherein the angle of incidence of the probing electron beam is irradiated with an inclination angle of approximately 17 ° in order to determine the size relationships in the lateral direction and in the lateral direction
- Elevation or thickness direction of the pyramidal structures 4 to show more clearly.
- the silicon structures 4 have a height which is on average about 1000 nm, so that in some embodiments a height is reached which is greater than the wavelengths of visible light.
- the height entered as a measure in FIG. 2 is to be converted from 603 nm to the real height. It is also possible to convert the vertical extent by up to 60% for lower pyramid-like needles, which achieve their effects from about 400 nm. This is done by compression of Figure 2 in the height direction to 40% of the height shown.
- pyramid-like structures 4 with a mean height in the range of 400 nm show excellent optical properties in many applications.
- an excellent antireflection in the visible wavelength range up to 3000 nm was observed.
- a mean maximum height of the silicon structures 4 can also be substantially 1000 nm.
- Figures 1 and 2 show that the lateral dimension of the silicon structures (at the foot) is typically less than 100 nm or significantly less, so that on average an aspect ratio of height to lateral dimension of 4, or even higher is achieved.
- FIGS. 1 and 2 which relate to a 6-inch (100) Si p-doped disk, a 10 ohm * cm resistor, and an oxide mask area greater than 90% (to substantially 93%). were produced in one
- Si slice temperature 27 degrees Celsius
- Plasma power 10O W
- Self-adjusting BIAS i.e., DC potential between the plasma atmosphere and the surface to be etched: varies by 350V (adjusts itself)
- process time of up to 20 min is also useful. Then the process results in an extremely high-quality antireflective coating of the surface nanostructured with the needles.
- gas flow rates of between 50 to 150 sccm have been provided for the reactive gas, ie SF ⁇ , C n F m or HCI / BCU.
- oxygen gas flow rates of 20 to 200 sccm are provided.
- the temperature of the substrate, and thus the base layer 3 is set to a range of 27 ° C ⁇ 5 ° C.
- the 6 "(inch, inch) disk was placed on an 8" disk in the RIE STS 320 system and the plasma can also act next to the 8 "disk be set in the range of 100 W to 300 W, which corresponds to a 6 inch disk power density of about 4 W / cm 2 to 12 W / cm 2 .
- corresponding parameter values for other etching systems and other degrees of coverage of the silicon base layer 3 to be structured with the pyramidal structures can be determined. For example, a lower degree of coverage of the silicon base layer may be taken into account by a lower gas flow rate of the reactive gas.
- the Si needles 4 having a height of about 1000 nm were generally randomly distributed at the areas not masked by the mask layer 5.
- silicon oxides or silicon nitrides are suitable.
- Machined disks with similar structures become completely black and showed a reflection of less than 0.4% for the wavelength range of 400 nm to 1000 nm, at the same time excellent homogeneity of this property over the entire wafer (disk).
- the investigations showed a still excellent anti-reflection behavior with reflections below 2%. The reflections recorded here (practically only) the reflections in all solid angles.
- the crystal damage caused by the plasma-assisted single-stage structuring process and the contamination are very low and are below the detection limit in the exemplary embodiments shown. There could be no Residual substances are detected after the plasma structuring process and the crystal quality of the silicon structures is almost identical to the crystal quality of the silicon base layer before the etching process.
- the needle portions of the pyramid-like needles are almost atomically pointed at its end 4a.
- the lateral dimensions of the end 4a are only a few nanometers.
- individual network planes (111) of the monocrystalline needle section can be clearly seen without crystal defects caused by the etching being recognizable.
- Fig. 3 shows a pyramid-like needle 4, a single tip 4a and an end portion with this tip 4a.
- the needles are almost atomically pointed at their end 4a, ie, the lateral dimensions of the end 4a are only a few nanometers and are thus smaller than 10 nm.
- the crystal direction is also perpendicular to Surface of the silicon base layer 3 registered. This direction corresponds to a [001] direction, since for the embodiment shown, the surface orientation is a (100) orientation.
- the end region with the tip end 4a extends substantially along the [001] direction with only a slight deviation of less than 10 °, so that the structural elements are aligned almost perpendicularly with only a few degrees deviation from the normal to the surface of the base layer 3 ,
- Figure 3a is properly aligned [001]. With the figures 3, 3a, the inclination of the side wall of a pyramid-like needle can be roughly determined. It is about 4 ° to the normal [001].
- the appearing lattice planes correspond to the (111) planes.
- the surface which is severely rugged after the process, significantly increases their surface area, which significantly alters their properties.
- the increased surface area offers a much larger attack surface for attaching molecules and can thus significantly increase the sensitivity of sensors.
- the pyramidal structures 4 are interesting in that they are smaller in their lateral size than the light wavelength (VIS / NIR) are and give by their needle shape, ie, by the small lateral dimension of the end portion 4a and the relatively large dimension at the bottom of the pyramidal structure, and the high aspect ratios, an almost perfect gradient layer.
- the refractive index changes gradually from the refractive index of the silicon to the refractive index of the medium surrounding the nanostructure 2, for example air.
- the nanostructure 2 thus allows an impedance matching or refractive index matching, which leads to an excellent broadband reflection suppression. Furthermore, it is known that strong bends, as they have the needle tips 4a, are particularly suitable for field emission.
- the examples thus provide methods and structures in which silicon structures with a large and adjustable aspect ratio occur, wherein due to the (special) parameter setting in the self-masking plasma etching process in a single etching step contamination and formation plasma-related crystal defects is kept low, so that with little effort for the one-step patterning process, the resulting structure can be used immediately without the need for further post-processing steps when needle-like silicon structures in high monocrystalline form are required.
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Abstract
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Application Number | Priority Date | Filing Date | Title |
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DE102005048366A DE102005048366A1 (en) | 2005-10-10 | 2005-10-10 | A process for the preparation of low-defect self-organized needle-like structures with nano-dimensions in the range below the usual light wavelengths with high aspect ratio |
PCT/EP2006/067248 WO2007042520A2 (en) | 2005-10-10 | 2006-10-10 | Self-organized pin-type nanostructures, and production thereof on silicon |
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EP1935010A2 true EP1935010A2 (en) | 2008-06-25 |
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EP06807129A Withdrawn EP1935010A2 (en) | 2005-10-10 | 2006-10-10 | Self-organized pin-type nanostructures, and production thereof on silicon |
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US (1) | US8058086B2 (en) |
EP (1) | EP1935010A2 (en) |
DE (1) | DE102005048366A1 (en) |
WO (1) | WO2007042520A2 (en) |
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DE102007051752B4 (en) * | 2007-10-30 | 2010-01-28 | X-Fab Semiconductor Foundries Ag | Light-blocking layer sequence and method for their preparation |
EP2336823A1 (en) * | 2009-12-18 | 2011-06-22 | Boegli-Gravures S.A. | Method and device for producing masks for a laser assembly for generating microstructures |
CN102646699B (en) * | 2012-01-13 | 2014-12-10 | 京东方科技集团股份有限公司 | Oxide TFT (thin film transistor) and manufacturing method thereof |
JP6361241B2 (en) * | 2014-04-04 | 2018-07-25 | 王子ホールディングス株式会社 | Fine structure |
CN109853044B (en) * | 2019-01-21 | 2021-06-15 | 南京航空航天大学 | Monocrystalline silicon surface composite microstructure based on full-wave band antireflection and preparation method thereof |
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US3493822A (en) * | 1966-02-24 | 1970-02-03 | Globe Union Inc | Solid state solar cell with large surface for receiving radiation |
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US4778563A (en) * | 1987-03-26 | 1988-10-18 | Applied Materials, Inc. | Materials and methods for etching tungsten polycides using silicide as a mask |
CA2027031A1 (en) | 1989-10-18 | 1991-04-19 | Loren A. Haluska | Hermetic substrate coatings in an inert gas atmosphere |
US5429708A (en) * | 1993-12-22 | 1995-07-04 | The Board Of Trustees Of The Leland Stanford Junior University | Molecular layers covalently bonded to silicon surfaces |
DE4415567B4 (en) | 1994-05-03 | 2004-11-04 | Robert Bosch Gmbh | Method for producing an SOI structure with an insulation layer on a silicon wafer and a silicon layer epitaxially applied thereon |
WO1996008036A1 (en) | 1994-09-02 | 1996-03-14 | Stichting Voor De Technische Wetenschappen | Process for producing micromechanical structures by means of reactive ion etching |
US6579777B1 (en) * | 1996-01-16 | 2003-06-17 | Cypress Semiconductor Corp. | Method of forming local oxidation with sloped silicon recess |
US6091021A (en) | 1996-11-01 | 2000-07-18 | Sandia Corporation | Silicon cells made by self-aligned selective-emitter plasma-etchback process |
US6038065A (en) | 1997-06-06 | 2000-03-14 | Raytheon Company | Infrared-transparent window structure |
DE19912737A1 (en) | 1998-03-19 | 2000-06-21 | Henning Nagel | Production of porous silicon oxide film useful as antireflection coating on glass or transparent plastics, involves using self-shading or atoms and molecules in plasma-enhanced chemical vapor deposition |
US6858462B2 (en) | 2000-04-11 | 2005-02-22 | Gratings, Inc. | Enhanced light absorption of solar cells and photodetectors by diffraction |
DE10036725C2 (en) | 2000-07-27 | 2002-11-28 | Infineon Technologies Ag | Process for producing a porous insulating layer with a low dielectric constant on a semiconductor substrate |
US6329296B1 (en) | 2000-08-09 | 2001-12-11 | Sandia Corporation | Metal catalyst technique for texturing silicon solar cells |
JP2002182003A (en) | 2000-12-14 | 2002-06-26 | Canon Inc | Antireflection functional element, optical element, optical system and optical appliance |
WO2004021452A2 (en) | 2002-08-29 | 2004-03-11 | X-Fab Semiconductor Foundries Ag | Integrated photosensitive structures and passivation method |
DE10239642B3 (en) | 2002-08-29 | 2004-06-24 | X-Fab Semiconductor Foundries Ag | Complementary metal oxide semiconductor/bipolar complementary metal oxide semiconductor - integrated circuit for camera chip has single individual layer as last layer of passivation system sealing off integrated circuit |
DE10239643B3 (en) | 2002-08-29 | 2004-06-17 | X-Fab Semiconductor Foundries Ag | Complementary metal oxide semiconductor/bipolar complementary metal oxide semiconductor - integrated circuit for camera chip has single individual layer as last layer of passivation system sealing off integrated circuit |
US6946362B2 (en) | 2002-09-06 | 2005-09-20 | Hewlett-Packard Development Company, L.P. | Method and apparatus for forming high surface area material films and membranes |
KR20050057208A (en) | 2002-09-06 | 2005-06-16 | 아사히 가라스 가부시키가이샤 | Polishing agent composition for insulating film for semiconductor integrated circuit and method for manufacturing semiconductor integrated circuit |
JP4140765B2 (en) | 2002-09-19 | 2008-08-27 | コバレントマテリアル株式会社 | Acicular silicon crystal and method for producing the same |
DE10350643B4 (en) | 2003-10-29 | 2008-12-04 | Infineon Technologies Ag | Method for producing an anti-reflective surface on optical integrated circuits |
DE10352423B3 (en) | 2003-11-10 | 2005-01-05 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Reducing the reflection on semiconductor surfaces in the manufacture of semiconductor substrates for solar cells comprises subjecting regions to dry chemical etching, in which the aspect ratio of recesses is obtained |
-
2005
- 2005-10-10 DE DE102005048366A patent/DE102005048366A1/en not_active Ceased
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2006
- 2006-10-10 WO PCT/EP2006/067248 patent/WO2007042520A2/en active Application Filing
- 2006-10-10 EP EP06807129A patent/EP1935010A2/en not_active Withdrawn
- 2006-10-10 US US12/089,724 patent/US8058086B2/en not_active Expired - Fee Related
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US20110127641A1 (en) | 2011-06-02 |
DE102005048366A1 (en) | 2007-04-19 |
US8058086B2 (en) | 2011-11-15 |
WO2007042520A3 (en) | 2007-06-07 |
WO2007042520A2 (en) | 2007-04-19 |
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