GB1558764A - Formation of contacts for semiconductor devices - Google Patents
Formation of contacts for semiconductor devices Download PDFInfo
- Publication number
- GB1558764A GB1558764A GB51147/75A GB5114775A GB1558764A GB 1558764 A GB1558764 A GB 1558764A GB 51147/75 A GB51147/75 A GB 51147/75A GB 5114775 A GB5114775 A GB 5114775A GB 1558764 A GB1558764 A GB 1558764A
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- United Kingdom
- Prior art keywords
- deposited material
- process step
- heating process
- contact
- initially
- Prior art date
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- Expired
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- 239000004065 semiconductor Substances 0.000 title claims description 50
- 230000015572 biosynthetic process Effects 0.000 title description 6
- 239000000463 material Substances 0.000 claims description 110
- 238000000034 method Methods 0.000 claims description 66
- 239000011521 glass Substances 0.000 claims description 49
- 238000010438 heat treatment Methods 0.000 claims description 41
- 239000011248 coating agent Substances 0.000 claims description 35
- 238000000576 coating method Methods 0.000 claims description 35
- 239000011159 matrix material Substances 0.000 claims description 34
- 238000010276 construction Methods 0.000 claims description 31
- 239000000470 constituent Substances 0.000 claims description 18
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 claims description 15
- 230000005855 radiation Effects 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 13
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 13
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 13
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 13
- 239000011230 binding agent Substances 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 8
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 7
- 238000007650 screen-printing Methods 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 239000004332 silver Substances 0.000 claims description 7
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 5
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 4
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 4
- 230000000996 additive effect Effects 0.000 claims description 4
- 239000004411 aluminium Substances 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 239000011651 chromium Substances 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 239000010931 gold Substances 0.000 claims description 4
- 229910052735 hafnium Inorganic materials 0.000 claims description 4
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 4
- 229910052748 manganese Inorganic materials 0.000 claims description 4
- 239000011572 manganese Substances 0.000 claims description 4
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 4
- 239000000155 melt Substances 0.000 claims description 4
- 239000006060 molten glass Substances 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 229910052715 tantalum Inorganic materials 0.000 claims description 4
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 4
- 230000008719 thickening Effects 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- QSGNKXDSTRDWKA-UHFFFAOYSA-N zirconium dihydride Chemical compound [ZrH2] QSGNKXDSTRDWKA-UHFFFAOYSA-N 0.000 claims description 4
- 229910000568 zirconium hydride Inorganic materials 0.000 claims description 4
- 239000006185 dispersion Substances 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 description 6
- -1 titanium hydride Chemical compound 0.000 description 5
- 229910000048 titanium hydride Inorganic materials 0.000 description 5
- 229910052729 chemical element Inorganic materials 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
- H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
- H01L23/3157—Partial encapsulation or coating
- H01L23/3171—Partial encapsulation or coating the coating being directly applied to the semiconductor body, e.g. passivation layer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/482—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of lead-in layers inseparably applied to the semiconductor body (electrodes)
- H01L23/4827—Materials
- H01L23/4828—Conductive organic material or pastes, e.g. conductive adhesives, inks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
- H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
- H01L23/532—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body characterised by the materials
- H01L23/53204—Conductive materials
- H01L23/5328—Conductive materials containing conductive organic materials or pastes, e.g. conductive adhesives, inks
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H10F77/00—Constructional details of devices covered by this subclass
- H10F77/20—Electrodes
- H10F77/206—Electrodes for devices having potential barriers
- H10F77/211—Electrodes for devices having potential barriers for photovoltaic cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Photovoltaic Devices (AREA)
Description
(54) IMPROVEMENTS RELATING TO THE FORMATION OF CONTACTS FOR
SEMICONDUCTOR DEVICES
(71) We, FERRANTI LIMITED, a Company registered under the Laws of Great
Britain, of Hollinwood in the County of
Lancaster, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the formation of contacts for semiconductor devices, especially, but not exclusively, for photovoltaic cells, and in particular for terrestrial solar cells.
It is an object of the present invention to provide an advantageous method of forming a contact on a surface of a semiconductor body of a device requiring, under normally encountered operating conditions, a relatively large current flow through the contact, the contact having a thickness of at least 1 micron. For convenience, in this specification such a contact will be referred to as "a contact of the kind referred to".
According to the present invention a method of manufacturing a semiconductor device includes the steps of forming a contact of the kind referred to on a surface of the semiconductor body of the device by forming on a layer of passivating material on the surface of a predetermined pattern of deposited material, the shape of the predetermined pattern in plan corresponding to the shape in plan of the required contact, the method also including a subsequent heating process step, the deposited material initially before the heating process step, includ
ing, in addition to a highly conductive metal, a glass frit, in the contact so obtained there being complex constructions of components in a glass matrix as herein defined, one type of complex construction of components in the glass matrix being formed with the parts of the passivating- material initially beneath the deposited material before the heating process step.
When in a method there are provided materials for a complex glass matrix together with added components, under appropriate conditions it is known for reactions to occur between the added components, within the glass matrix, and/or for chemical elements or compounds of the added components to react with the glass matrix, and/ or for other chemical elements or compounds, initially in the vicinity of the glass matrix, to enter the glass matrix, and possibly either to react with the glass matrix, or with the added components. Usually the complex glass matrix remains, but possibly in a form modified by the presence of the added components, and/or by the other chemical elements or compounds, initially in the vicinity of the glass matrix. In any event the construction of the resulting material is more complex than that of the complex, modified or unmodified, glass matrix; and usually the construction is not uniform throughout the material, there being considered to be different types of construction within the material. The term "complex constructions of components in a glass matrix as herein defined" is used in this specification and the accompanying claims to refer to each such type of construction within the material resulting from employing such a method. In such a method in accordance with the present invention, each such complex construction of components in a glass matrix is required to be electrically conductive, because it is required to be included in a contact for a semiconductor device.
Because the parts of the passivating layer initially beneath the deposited material form part of said one type of complex construction of components in the glass matrix, the contact extends, at least, through an aperture in the remaining parts of the passivating layer, to be contiguous with the semiconductor body.
Said one type of complex construction of components in the glass matrix has a a constituent either the passivating material; or an element, or compound, provided by the passivating material.
The semiconductor body may be of any known material.
The passivating layer may comprise any known material.
When the passivating layer is of silicon oxide the deposited material includes an active constituent to react, in the heating process t' with the parts of the passivating layer initially beneath the deposited material, to form said one type of complex construction of components in the glass matrix. The passivating layer of silicon oxide may be formed in any conventional manner.
The active constituent of the deposited material may comprise, or include, titanium, zirconium, manganese, hafnium, vanadium, tantalum, or chromium. It must be capable of being finely divided.
The active constituent of the deposited material in its initial form may be in the form of a compound such as titanium hydride or zirconium hydride, or it may be a chemical elemental, for example, manganese.
The initial proportion by weight of the active constituent of the deposited material may be in the range 1 to 10%.
The passivating layer, alternatively, may be of titanium oxide. The semiconductor body may be provided initially before the heating process step with a coating of tetra butyl titanate, and in the heating process step the parts of the coating not beneath the deposited material being converted to said titanium oxide layer, and the parts of the coating initially beneath the deposited material are converted to said one type of complex construction of components in the glass matrix. The term "deposited material" will be used in this specification and accompanying claims as a reference only to the deposited material including the glass frit and the highly conductive metal, and not to a coating providing a passivating layer on the semiconductor body. The tetra butyl titanate may be applied to the semiconductor body in the form of a dispersion in butyl acetate. Further, the term "passivating layer" will be used to refer to the coating of tetra butyl titanate, from which a passivating layer of titanium oxide is formed, where appropriate, and especially in relation to the formation of said one type of complex construction within the contact of the kind referred to.
Before the heating process step the proportion by weight of the glass frit in the deposited material may be in the range of 10 to 45%. The presence of the glass in the completed contact of the kind referred to ensures that the highly conductive metal adheres in a satisfactory manner to the semiconductor body.
The highly conductive metal in the deposited material may be silver, nickel, copper, gold or aluminium. Before the heating process step the proportion by weight of the highly conductive metal in the deposited material may be in the range 50 to 90%.
Conveniently, in the said heating process step there is a stage with a maximum temperature of 500"C, and in which stage the glass frit melts, and said one type of complex construction of components in the glass matrix is formed with the passivating material, there is a further stage with a maximum temperature of 700"C in which the highly conductive metal becomes uniformly dispersed in the molten glass phase, and possibly the final stage is one in which the device is cooled in a controlled manner to ensure that there is no stress within the structure. Such a heating process step, in which the maximum temperature obtained does not exceed 700"C, does not adversely affect the performance of the semiconductor device.
To facilitate the deposition, the deposited material in its initial form may include a binder, and a solvent for the binder, to be removed in the heating process step.
Conveniently, in the heating process step there is a stage with a maximum temperature of 3000 C, in which stage volatile constituents of the deposited material before the heating process step are removed.
A thickening additive may be included in the deposited material.
Inevitably a method according to the present invention, and in particular the formation of a contact of the kind referred to, is simple and inexpensive, because the deposited material from which the contact is formed is not required to be deposited within an aperture or recess formed by photolithographic techniques in the passivating layer, where a part of the contact is required to be contiguous with the semiconductor body; and because the predetermined pattern of deposited material is not required to be in registration with such an aperture or recess in the passivating layer.
The predetermined pattern of deposited material may be formed on the passivating layer in any convenient way. The predetermined pattern of deposited material may be provided from an initially continuous layer by employing known photolithographic techniques. Alternatively, the predetermined pattern of deposited material may be provided by a silk screen printing process step, such step being simple and inexpensive to perform, and the degree of resolution of the predetermined pattern of deposited material so provided being sufficient to form a contact of the kind referred to. A silk screen printing process step also has a high throughput rate of manufactured devices.
For these reasons, the method has particular application for the manufacture of terrestrial solar cells.
According to another aspect the present invention comprises a semiconductor device manufactured by a method referred to above.
The device may comprise a photovoltaic cell, such as a terrestrial solar cell, the passivating layer also acting as a relatively thin, transparent, antirefiection coating of the device, the coating having an optical thickness substantially equal to an odd number, preferably, one or three, of quarters of the mean wavelength of the incident radiation to which the device is responsive.
Alternatively, the device may comprise any type of power semiconductor device.
Methods of manufacturing photovoltaic cells, especially terrestrial solar cells, and according to the present invention, will now be described by way of example.
EXAMPLE 1.
A radiation-sensitive P-N junction is provided in a silicon semiconductor body of the photovoltaic cell by a known process step.
The P-N junction extends parallel to a surface of the semiconductor body, on which radiation is to be incident, the device to be responsive to the radiation.
During the formation of the P-N junction, or subsequently thereto, a passivating layer of silicon oxide is provided on the surface of the semiconductor body. When the silicon oxide of the passivating layer is formed in a diffusion process step, when the radiation-sensitive P-N junction is formed, the layer may be doped with phosphorus, which is advantageous for passivation purposes.
The silicon oxide layer is required to be relatively thin and tansparent, and also acts as an antireflection coating for the device.
A contact of the kind referred to is provided on the surface of the semiconductor body to be exposed to incident radiation by depositing material on the layer of passivating material by a silk screen printing process step. The deposited material is in the form of a predetermined pattern, the shape of the predetermined pattern in plan corresponding to the shape in plan of the desired contact.
The deposited material comprises : - 70.0% by weight silver,
4.0% by weight titanium hydride,
20.0% by weight glass frit, and
6.0% by weight of a cellulose binder and
solvent therefor.
The device is then passed through a belt furnace.
In a first stage of the heating process step, having a maximum temperature of 300"C, the volatile constituents of the deposited material are removed. In a second stage, having a maximum temperature of 500"C, the glass frit melts and forms complex constructions of components in the molten glass phase; the active constituent of the deposited material, comprising the titanium hydride, reacts with the parts of the silicon oxide passivating material therebeneath, to form one type of the complex construction of components in a glass matrix as herein defined. In a third stage, having a maximum temperature of 700"C, the silver becomes uniformly dispersed in the molten glass phase. In a fourth, and final, stage the device is cooled in a controlled manner to ensure that there is no stress within the structure.
Said one type of complex construction of components in the glass matrix provided with the passivating layer has a constituent either the passivating material, or an element, or compound, provided by the passivating material.
Thus, the contact of the kind referred to is completed, and includes complex constructions of components in the solid glass matrix, as herein defined, and is contiguous with the semiconductor body, by reacting with the parts of the passivating layer initially beneath the deposited material.
Thus, the contact extends through an aperture in the remaining parts of the passivating layer. The thickness of the contact is 10 microns, and is capable of carrying a relatively large current flow under normally encountered operating conditions for the device. The presence of the glass in the contact ensures that the silver adheres in a satisfactory manner to the semiconductor body.
The photovoltaic cell also includes, provided in any known manner, a contact on the opposing surface of the semiconductor body. If this other contact is provided before the contact of the kind referred to, this other contact may be coated with the deposited material referred to above, and so has a layer including the highly conductive metal of the contact of the kind referred to.
The highly conductive metal deposited in the silk screen printing process step has a proportion by weight of the deposited material in its initial form in the range 50 to 90%. The deposited material may have any highly conductive metal instead of silver and, for example, may have nickel, copper, gold or aluminium.
The active constituent of the deposited material in its initial form, and to react with the passivating material, may comprise zirconium hydride instead of titanium hydride.
Alternatively, it may not comprise a com pound in its initial form in the deposited material, but instead comprise a chemical element such as manganese. Further, the active constituent may comprise, or include, titanium, zirconium, manganese, hafnium, vanadium, tantalum, or chromium. It must be capable of being in a finely divided form.
The proportion by weight of the active constituent in the deposited material in its initial form is in the range 1 to 10%.
The proportion by weight of the glass frit in the deposited material in its initial form is in the range 10 to 45%.
The presence of phosphorus in the passivating layer, for example, the phosphorus being introduced in a previous diffusion process step, may assist the reaction between the active constituent of the deposited material and the passivating material.
However, the silicon oxide passivating material may be formed other than in a diffusion process step, and may be deposited on the semiconductor body from an atmosphere including silane.
In the photovoltaic cell described above.
the contact of the kind referred to, provided on the surface of the semiconductor body to be exposed to incident radiation to which the device is responsive, is required to have a shape in plan in the form of a predetermined pattern so as to mask a minimum proportion of the surface commensurate with the device having a satisfactory operating performance.
Further, it is desirable that the p?SSiV- ating layer-antireflection coating has an optical thickness substantially equal to an odd number of quarters of the mean wavelength of the incident radiation, so that an approximate optical match for the semiconductor body is obtained, the optical thickness of the passivating layer being the product of its physical thickness and its refractive index. Preferably a passivating layer with an optical thickness of approximately one-quarter, or three-quarters, of the wavelength is provided. For one particular embodiment of the photovoltaic cell, the mean wavelength of the incident radiation is 6000A approximately, and the refractive index of the silicon oxide passivating layer is approximately 1.4. Thus, the physical thickness of the passivating layer is required to be substantially 1000A or 3000A. Whilst the antireflection coating may have an optical thickness substantially equal to any odd number of quarters of the mean wavelength of the incident radiation, it is undesirable to having an antir flection coating with a thickness greater than 10,000 when the contact of the kind referred to is to be formed, partially, by converting the parts of the passivating layer initially underneath the deposited material to a complex construction of components within the glass matrix.
In any event, it is desirable that the surface of the body is covered with a passivating layer except where the surface ib to be contiguous with the contact of the kind referred to provided on the surface. If a method according to the present invention is not employed, it is necessary to form by photolithographic techniques an aperture or recess in the passivating layer, which is undesirable.
EXAMPLE 2.
The method described above in Example 1 is modified in that any silicon oxide on the silicon semiconductor body of the device is removed before providing the contacts.
An antireflection coating of titanium oxide is provided on the surface of the semiconductor body to be exposed to incident radiation to which the device is responsive, the optical thickness of the titanium oxide layer is substantially equal to an odd number of quarters of the mean wavelength of the incident radiation. Titanium oxide is a better anti reflection coating than silicon oxide. The antireflection coating also acts as the passivating layer on the semiconductor body.
Because the antireflection coating-passivating layer is of titanium oxide the titanium hydride of Example 1 is omitted from the deposited material of Example 2.
Initially, before the provision of the deposited material, a thin coating of tetra butyl titanate is provided on the surface of of the semiconductor body to be exposed to incident radiation, after silicon oxide, if present, has been removed from - the body.
In order to obtain a coating of the required small thickness the tetra butyl titanate initially is in a suitable dispersant, such as butyl acetate, which has a suitable viscosity, is miscible with tetra butyl titanate, and does not react with, or hydrolyse, the tetra butyl titanate. 30% by weight of tetra butyl titanate in 70% by weight of butyl acetate is employed.
The required coating is spun onto the semiconductor body, and initially is solely of tetra butyl titanate. The coating is dried by being heated at a temperature of 130"C for 5 minutes in an atmosphere of nitrogen. The surface of the coating is then sufficiently resistant to light abrasion to allow the deposited material, to form the desired contact of the kind referred to, to be printed onto the coating, with the required predetermined shape in plan.
The deposited material to form the desired contact, and the coating, are then fired in the same multi-stage heating process step as in Example 1. In this heating process step, in addition to forming the contact, there is conversion of the parts of the coat ing not beneath the deposited material to the passivating layer of the titanium oxide of the required thickness, and conversion of the parts of the tetra butyl titanate coating initially beneath the deposited material to said one type of complex construction of components in the glass matrix of the contact. The contact is provided contiguous with the semiconductor body.
The method according to present invention may be modified in various ways.
The semiconductor body may not be of silicon.
The passivating layer may be of any known material.
Any type of power semiconductor device may be manufactured by a method according to the present invention, in which case it is not required that the passivating layer also acts as an antireflection coating.
The predetermined pattern of deposited material may be formed in any convenient way, instead of being deposited by a silk screen printing process step. Hence, for example, it may be provided by employing photolithographic techniques with an initially continuous layer of the deposited material.
The binder, and the dispersive medium for the binder, may be omitted, obviating the need for a stage in the heating process step with a maximum temperature of 300"C.
A thickening additive may be included in the deposited material.
A contact of the kind referred to, and provided by a method according to the present invention has a minimum thickness of I micron, and is capable of carrying a relatively large current under normally encountered operating conditions for the device manufactured by the method.
WHAT WE CLAIM IS:- 1. A method of manufacturing a semiconductor device, including the steps of forming a contact of the kind referred to on a surface of the semiconductor body of the device by forming on a layer of passivating material on the surface a predetermined pattern of deposited material, the shape of the predetermined pattern in plan corresponding to the shape in plan of the required contact, the method also including a subsequent heating process step, the deposited material initially, before the heating process step, including, in addition to a highly conductive metal, a glass frit, in the contact so obtained, there being complex construction of components in a glass matrix as herein defined, one type of complex construction of components in the glass matrix being formed with parts of the passivatina layer initially beneath the deposited material before the heating process step.
2. A method as claimed in claim 1 in which the passivating layer is of silicon oxide, and the deposited material includes an active constituent to react, in the heating process step, with the parts of the passivating layer initially beneath the deposited material, to form said one type of complex construction of components in the glass matrix.
3. A method as claimed in claim 2 in which the active constitutent of the deposited material comprises, or includes titanium, zirconium, manganese, hafnium, vanadium, tantalum or chromium.
4. A method as claimed in claim 3 in which the active constitutent of the deposited material in its initial form is titanium hy drifle. or zirconium hydride, or manganese.
5. A method as claimed in any one of claims 2 to 4 in which the initial proportion by weight of the active constituent of the deposited material is in the range 1 to 10%.
6. A method as claimed in claim 1 in which the passivating layer is of titanium oxide.
7. A method as claimed in claim 6 in which the semiconductor body is provided initially before the heating process step with a coating of tetra butyl titan ate, and in the heating process step the parts of the coating not beneath the deposited material being converted to said titanium oxide layer, and the parts of the coating initially beneath the deposited material are converted to said one type of complex construction of components in the glass matrix.
S. A method as claimed in claim 7 in which the tetra butyl titanate is applied to the semiconductor body in the form of a dispersion in butyl acetate.
9. A method as claimed in any one of the preceding claims in which before the heating process step proportion by weight of the glass frit in the deposited material is in the range 10 to 45%.
10. A method as claimed in any one of the preceding claims in which the deposited material includes a highly conductive metal such as silver, nickel, copper, gold or aluminium.
11. A method as claimed in any one of the preceding claims in which before the heating process step proportion by weight of the highly conductive metal in the deposited material is in the range 50 to 90%.
12. A method as claimed in any one of the preceding claims having the said heating process step including a stage with a maximum temperature of 500"C, and in which stage the glass frit melts and said one type of complex construction of components in the glass matrix is formed with the passivating material, and a further stage with a maximum temperature of 700"C in which
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (24)
1. A method of manufacturing a semiconductor device, including the steps of forming a contact of the kind referred to on a surface of the semiconductor body of the device by forming on a layer of passivating material on the surface a predetermined pattern of deposited material, the shape of the predetermined pattern in plan corresponding to the shape in plan of the required contact, the method also including a subsequent heating process step, the deposited material initially, before the heating process step, including, in addition to a highly conductive metal, a glass frit, in the contact so obtained, there being complex construction of components in a glass matrix as herein defined, one type of complex construction of components in the glass matrix being formed with parts of the passivatina layer initially beneath the deposited material before the heating process step.
2. A method as claimed in claim 1 in which the passivating layer is of silicon oxide, and the deposited material includes an active constituent to react, in the heating process step, with the parts of the passivating layer initially beneath the deposited material, to form said one type of complex construction of components in the glass matrix.
3. A method as claimed in claim 2 in which the active constitutent of the deposited material comprises, or includes titanium, zirconium, manganese, hafnium, vanadium, tantalum or chromium.
4. A method as claimed in claim 3 in which the active constitutent of the deposited material in its initial form is titanium hy drifle. or zirconium hydride, or manganese.
5. A method as claimed in any one of claims 2 to 4 in which the initial proportion by weight of the active constituent of the deposited material is in the range 1 to 10%.
6. A method as claimed in claim 1 in which the passivating layer is of titanium oxide.
7. A method as claimed in claim 6 in which the semiconductor body is provided initially before the heating process step with a coating of tetra butyl titan ate, and in the heating process step the parts of the coating not beneath the deposited material being converted to said titanium oxide layer, and the parts of the coating initially beneath the deposited material are converted to said one type of complex construction of components in the glass matrix.
S. A method as claimed in claim 7 in which the tetra butyl titanate is applied to the semiconductor body in the form of a dispersion in butyl acetate.
9. A method as claimed in any one of the preceding claims in which before the heating process step proportion by weight of the glass frit in the deposited material is in the range 10 to 45%.
10. A method as claimed in any one of the preceding claims in which the deposited material includes a highly conductive metal such as silver, nickel, copper, gold or aluminium.
11. A method as claimed in any one of the preceding claims in which before the heating process step proportion by weight of the highly conductive metal in the deposited material is in the range 50 to 90%.
12. A method as claimed in any one of the preceding claims having the said heating process step including a stage with a maximum temperature of 500"C, and in which stage the glass frit melts and said one type of complex construction of components in the glass matrix is formed with the passivating material, and a further stage with a maximum temperature of 700"C in which
the highly conductive metal becomes uniformly dispersed in the molten glass phase.
13. A method as claimed in any one of the preceding claims in which the heating process step includes a final stage in which the device is cooled in a controlled manner to ensure that there is no stress within the structure.
14. A method as claimed in any one of the preceding claims in which the deposited material in its initial form before the heating process includes a binder, and a solvent for the binder, to be removed in the heating process step.
15. A method as claimed in any one of the preceding claims having a heating process step including a stage with a maximum temperature of 3000 C, in which stage volatile constituents of the deposited material before the heating process step are removed.
16. A method as claimed in any one of the preceding claims in which the deposited material includes a thickening additive.
17. A method as claimed in any one of the preceding claims in which the predetermined pattern of deposited material is provided from an initially continuous layer by employing known photolithographic techniques.
18. A method as claimed in any one of claims 1 to 16 in which the predetermined pattern of deposited material is provided by a silk screen printing process step.
19. A semiconductor device manufactured by a method as claimed in any one of the preceding claims.
20. A device as claimed in claim 19 comprising a photovoltaic cell, the passivating layer acting as a relatively thin, transparent, antireflection coating of the device, the coating having an optical thickness substantially equal to an odd number of quarters of the mean wavelength of the incident radiation to which the device is responsive.
21. A device as claimed in claim 20 with the antireflection coating having an optical thickness substantially equal to one quarter or three-quarters of the mean wavelength of the incident radiation to which the device is responsive.
22. A device as claimed in claim 19 comprising a power semiconductor device.
23. A method of manufacturing a semiconductor device substantially as described herein with referenc to Examlpe 1 or to
Example 2.
24. A semiconductor device manufactured by a method substantially as described herein with reference to Example 1 or to
Example 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB51147/75A GB1558764A (en) | 1976-11-15 | 1976-11-15 | Formation of contacts for semiconductor devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB51147/75A GB1558764A (en) | 1976-11-15 | 1976-11-15 | Formation of contacts for semiconductor devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1558764A true GB1558764A (en) | 1980-01-09 |
Family
ID=10458839
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB51147/75A Expired GB1558764A (en) | 1976-11-15 | 1976-11-15 | Formation of contacts for semiconductor devices |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1558764A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0052791A1 (en) * | 1980-11-26 | 1982-06-02 | E.I. Du Pont De Nemours And Company | Aluminum-magnesium alloys in low resistance contacts to silicon coated with Si3N4 |
| US4375007A (en) * | 1980-11-26 | 1983-02-22 | E. I. Du Pont De Nemours & Co. | Silicon solar cells with aluminum-magnesium alloy low resistance contacts |
| EP0102035A2 (en) * | 1982-08-20 | 1984-03-07 | Hitachi, Ltd. | Electrode material for semi-conductor devices |
| DE3318683C1 (en) * | 1983-05-21 | 1984-12-13 | Telefunken electronic GmbH, 7100 Heilbronn | Alloyed contact for n-conducting GaAlAs semiconductor material |
| FR2575331A1 (en) * | 1984-12-21 | 1986-06-27 | Labo Electronique Physique | HOUSING FOR ELECTRONIC COMPONENT |
| EP0205686A1 (en) * | 1985-06-13 | 1986-12-30 | Kidd, Inc. | Die-bonding electroconductive paste |
| US5380371A (en) * | 1991-08-30 | 1995-01-10 | Canon Kabushiki Kaisha | Photoelectric conversion element and fabrication method thereof |
| WO2006005317A3 (en) * | 2004-07-06 | 2006-06-15 | Epcos Ag | Method for the production of an electric component and component |
-
1976
- 1976-11-15 GB GB51147/75A patent/GB1558764A/en not_active Expired
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0052791A1 (en) * | 1980-11-26 | 1982-06-02 | E.I. Du Pont De Nemours And Company | Aluminum-magnesium alloys in low resistance contacts to silicon coated with Si3N4 |
| US4375007A (en) * | 1980-11-26 | 1983-02-22 | E. I. Du Pont De Nemours & Co. | Silicon solar cells with aluminum-magnesium alloy low resistance contacts |
| EP0102035A2 (en) * | 1982-08-20 | 1984-03-07 | Hitachi, Ltd. | Electrode material for semi-conductor devices |
| EP0102035A3 (en) * | 1982-08-20 | 1986-03-26 | Hitachi, Ltd. | Electrode material for semi-conductor devices |
| DE3318683C1 (en) * | 1983-05-21 | 1984-12-13 | Telefunken electronic GmbH, 7100 Heilbronn | Alloyed contact for n-conducting GaAlAs semiconductor material |
| US4613890A (en) * | 1983-05-21 | 1986-09-23 | Telefunken Electronic Gmbh | Alloyed contact for n-conducting GaAlAs-semi-conductor material |
| EP0188838A1 (en) * | 1984-12-21 | 1986-07-30 | Laboratoires D'electronique Et De Physique Appliquee L.E.P. | Housing for an electronic component |
| FR2575331A1 (en) * | 1984-12-21 | 1986-06-27 | Labo Electronique Physique | HOUSING FOR ELECTRONIC COMPONENT |
| EP0205686A1 (en) * | 1985-06-13 | 1986-12-30 | Kidd, Inc. | Die-bonding electroconductive paste |
| US5380371A (en) * | 1991-08-30 | 1995-01-10 | Canon Kabushiki Kaisha | Photoelectric conversion element and fabrication method thereof |
| WO2006005317A3 (en) * | 2004-07-06 | 2006-06-15 | Epcos Ag | Method for the production of an electric component and component |
| US7928558B2 (en) | 2004-07-06 | 2011-04-19 | Epcos Ag | Production of an electrical component and component |
| US8415251B2 (en) | 2004-07-06 | 2013-04-09 | Epcos Ag | Electric component and component and method for the production thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |