DE102020120420A1 - proceedings - Google Patents

Abstract

According to various embodiments, a method may include: sputtering a semiconductor material using a plasma, the plasma including krypton; Coating a substrate with the sputtered semiconductor material.

Description

Various example embodiments relate to a method.

In general, workpieces or substrates can be processed, e.g. machined, coated, heated, etched and/or structurally modified. One method for coating a substrate is, for example, cathode sputtering (so-called sputtering). For example, one layer or multiple layers can be deposited on a substrate by means of sputtering. For this purpose, a plasma-forming gas can be ionized by means of a cathode, it being possible for a material to be deposited (also referred to as target material) of the cathode to be sputtered by means of the plasma formed in the process. The sputtered target material can then be brought to a substrate where it can deposit and form a layer.

According to various embodiments, a method is provided that improves the electrical properties of a sputtered semiconductor layer. Clearly, it has been recognized that the use of krypton as the plasma-forming gas makes it possible to form a semiconductor layer whose carrier lifetime is longer by sputtering.

• 1 und 2 jeweils eine Sputtervorrichtung gemäß verschiedenen Ausführungsformen in verschiedenen schematischen Seitenansichten oder Querschnittsansichten;
• 3 eine Vakuumanordnung gemäß verschiedenen Ausführungsformen in einer schematischen Seitenansicht oder Querschnittsansicht;
• 4 ein Verfahren gemäß verschiedenen Ausführungsformen in einem schematischen Ablaufdiagramm;
• 5 und 6 jeweils ein Halbleiterbauelement gemäß verschiedenen Ausführungsformen in einer schematischen Seitenansicht oder Querschnittsansicht;
• 7 ein Verfahren gemäß verschiedenen Ausführungsformen in einem schematischen Ablaufdiagramm;
• 8 und 9 jeweils ein Diagramm gemäß verschiedenen Ausführungsformen;
• 10, 11 und 12 jeweils ein Diagramm gemäß verschiedenen Ausführungsformen; und
• 13 ein Verfahren gemäß verschiedenen Ausführungsformen in einem schematischen Ablaufdiagramm.

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• 1 and 2 each a sputtering device according to different embodiments in different schematic side views or cross-sectional views;
• 3 a vacuum arrangement according to various embodiments in a schematic side view or cross-sectional view;
• 4 a method according to various embodiments in a schematic flowchart;
• 5 and 6 each a semiconductor device according to various embodiments in a schematic side view or cross-sectional view;
• 7 a method according to various embodiments in a schematic flowchart;
• 8th and 9 each a diagram according to different embodiments;
• 10 , 11 and 12 each a diagram according to different embodiments; and
• 13 a method according to various embodiments in a schematic flowchart.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "front", "rear", etc. is used with reference to the orientation of the figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features of the various exemplary embodiments described herein can be combined with one another unless specifically stated otherwise. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Within the scope of this description, the terms “connected”, “connected” and “coupled” are used to describe both a direct and an indirect connection (e.g. ohmic and/or electrically conductive, e.g. an electrically conductive connection), a direct or indirect connection and a direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference symbols, insofar as this is appropriate.

According to various embodiments, the term “coupled” or “coupling” can be understood in the sense of a (eg mechanical, hydrostatic, thermal and/or electrical), eg direct or indirect, connection and/or interaction. A plurality of elements can be coupled to one another, for example, along an interaction chain, along which the interaction can be exchanged, for example a fluid (then also referred to as coupled in a fluid-conducting manner). For example, two elements coupled to one another can exchange an interaction with one another, eg a mechanical, hydrostatic, thermal and/or electrical interaction. A coupling of several vacuum components (eg valves, pumps, chambers, etc.) to one another can include that they are coupled to one another in a fluid-conducting manner. According to various In some embodiments, “coupled” can be understood in the sense of a mechanical (eg physical or bodily) coupling, eg by means of direct physical contact. A clutch can be set up to transmit a mechanical interaction (eg force, torque, etc.).

Controlling can be understood as intentional influencing of a system. The current state of the system (also referred to as the actual state) can be changed according to a specification (also referred to as the target state). Regulation can be understood as control, whereby a change in the state of the system due to disturbances is also counteracted. Clearly, the controller can have a forward-pointing control path and thus clearly implement a sequence control that converts an input variable (e.g. the specification) into an output variable. However, the controlled system can also be part of a control circuit, so that a control is implemented. In contrast to the purely forward-oriented sequence control, the regulation has a continuous influence of the output variable on the input variable, which is brought about by the control loop (the so-called feedback). In other words, regulation can be used as an alternative or in addition to the control, or regulation can take place as an alternative or in addition to the control. The state of the system (also referred to as the operating point) can be represented by one or more controlled variables of the system, the actual value of which represents the actual state of the system and the target value (also referred to as the reference value) the target state of the system represented. In a regulation, an actual state of the system (e.g. determined based on a measurement) is compared with the target state of the system and one or more controlled variables are influenced by means of a corresponding manipulated variable (using an actuator) in such a way that the deviation of the actual state is minimized from the target state of the system.

The term "sputtering" refers to the atomization of a material (also known as a coating material or target material) using a plasma. The sputtered components of the target material are thus separated from one another and can be deposited elsewhere, for example to form a layer. The sputtering can take place by means of a so-called sputtering device, which can have one or more than one magnet system (then also referred to as a magnetron). The target material can be provided by means of a so-called sputtering target, which can be, for example, tubular (then also referred to as tubular target) or plate-shaped (then also referred to as plate target or planar target). To generate the plasma, a voltage (also referred to as sputtering voltage) can be applied to the sputtering target (also referred to as target for short), so that the sputtering target is operated as a cathode. Even if the sputtering voltage has an alternating voltage, the terminology of the cathode is often retained.

If the magnetron has two sputtering targets (e.g. planar targets) (then also referred to as a double magnetron), one of the sputtering targets can be operated as an anode and the other sputtering target as a cathode, so that the sputtering voltage is applied between the two sputtering targets. In order to atomize both sputtering targets, the sputtering voltage can be cyclically reversed so that an alternating voltage is present between the two sputtering targets (also referred to as AC sputtering). A frequency of the AC voltage (ie, at which the polarity of the two sputtering targets is reversed) may be greater than about 1 Hertz (Hz), e.g. greater than about 10 Hz, e.g. greater than about 100 Hz, e.g. greater than about 1 kilohertz (kHz) , for example greater than about 10 kHz, for example in a range of about 100 kHz (then also referred to as MF sputtering). In principle, however, DC voltage can also be used as sputtering voltage (also referred to as DC sputtering). Optionally, the DC voltage (e.g. bipolar) can be pulsed (also referred to as pulsed DC sputtering).

For sputtering, the sputtering target can be arranged in a vacuum processing chamber (also referred to simply as a vacuum chamber), so that the sputtering can take place in a vacuum. To this end, the environmental conditions (the process conditions) within the vacuum processing chamber (e.g. pressure, temperature, gas composition, etc.) can be adjusted or regulated during sputtering. The vacuum processing chamber can, for example, be set up to be airtight, dust-tight and/or vacuum-tight, so that a gas atmosphere with a predefined composition (also referred to as working atmosphere) or a predefined pressure (also referred to as working pressure) can be provided within the vacuum processing chamber (e.g. according to a setpoint). For example, a working gas can be provided inside the vacuum processing chamber, which denotes the plasma-forming gas or the plasma-forming gas mixture.

In order to effectively atomize (also known as sputtering) the target material, the tubular target can be rotated around the magnet system. For this purpose, the tube target or its target material can be configured in a tube shape, with the magnet system being arranged inside the tube target can, so that the tubular target can be rotated around the magnet system. The tubular target can have a tube, for example, on which the target material can be attached as a layer on an outer lateral surface of the tube and can partially cover the lateral surface of the tube. However, the tube target can also be formed from the target material.

The tube target can be rotatably mounted by means of a bearing device, wherein the bearing device can optionally provide a supply of the tube target (e.g. with electrical power and cooling fluid). For example, the bearing device can have two so-called end blocks, by means of which the tubular target is supported at mutually opposite end sections, the end blocks being able to provide a supply of the tubular target (e.g. with electrical power and cooling fluid).

If the storage device has two end blocks, one of the end blocks (the so-called drive end block) can have a drive train which is coupled to a drive device (also referred to as a target drive) for rotating the tubular target; and the respective other of the end blocks (the so-called media end block) can have a fluid line for supplying and removing cooling fluid (e.g. a water-based mixture) which can be passed through the target. For example, the two end blocks are mounted in a suspended manner from a chamber ceiling (i.e., a chamber lid).

However, exactly one end block (also referred to as a compact end block) can also be used, which has the drive train and the fluid line and thus jointly provides the functions of a drive end block and a media end block. For example, the side of the tubular target opposite the compact endblock can be cantilevered (i.e., hang freely) in what is referred to as a cantilever configuration. The compact endblock may be mounted in a cantilever configuration on a sidewall of the vacuum chamber through which the axis of rotation of the tubular target extends. However, the side of the tubular target opposite the compact end block can also be mounted by means of a bearing block (clearly a counter bearing), which is referred to as a bearing block configuration. The pedestal can also be provided by means of a passive end block, i.e. an end block which does not exchange energy or material with the tube target but only supports it.

In the case of a planar target that does not have to be mounted so that it can rotate, the mounting device can have a rigid frame that holds the planar target. For example, the planar target may have one or more than one plate (e.g., tile), with multiple plates held side by side.

The bearing device can optionally (e.g. in the case of a tube target and a planar target) have a carrier (also referred to as a magnet carrier) which is set up to hold the magnet system. The magnet carrier can, for example, be hollow (e.g. having a tube) and be fluidically coupled at the end to an end block which holds the magnet carrier (e.g. to its fluid line) so that the cooling fluid can be exchanged with the end block. On the side opposite the end block, the tube can be closed at the end, for example, and can have a lateral opening there through which the cooling fluid can pass. The magnet carrier can be round or polygonal, e.g. having a round tube or a square tube. The magnet carrier and/or the magnet system can have a length (expansion along the axis of rotation) in a range from approximately 1 m to approximately 6 m, for example in a range from approximately 2 m to approximately 5 m.

The target and/or the cooling fluid can be subjected to voltages greater than about 50 V for sputtering. Clearly, an electrical voltage (also referred to as process voltage) can be applied to the target for sputtering, wherein the cooling fluid can be electrically coupled to the target, so that the cooling fluid and the target can have essentially the same electrical potential. The electrical power converted during sputtering is mainly absorbed by the plasma (also referred to as plasma power) and can therefore depend on the size (e.g. length) of the target and can range from about 1 kW per meter to about 30 kW per meter (des Targets) lie, with an AC voltage or pulsed DC voltage optionally being able to be used as the process voltage.

A drive device can be understood here as a converter which is set up to convert electrical energy into mechanical energy. A drive device can, for example, comprise an electric motor (e.g. with electric coils). A drive device can have, for example, a compressor and a reciprocating piston coupled thereto. A drive device can have one or more than one piezo element, for example. For example, the drive device can be set up to output the mechanical energy by means of a torque or a rotary movement.

According to various embodiments, the production of contact layers in crystalline photovoltaics, for example a doped aSi layer (amorphous silicon layer), is provided by means of a sputtering method. A dopant used herein can be, for example, phosphorus or boron.

With regard to a chemical composition, the molar fraction can be used as a measure of a concentration herein. The mole fraction (also referred to as mole fraction) can be understood (e.g. defined according to DIN 1310) as a content variable, i.e. a physico-chemical variable that indicates the amount of substance of a mixture component under consideration in relation to the sum of the amounts of substance of all components of the mixture. The mole fraction clearly indicates the relative proportion of the mole amount of a mixture component under consideration in the total mass of the mixture. In the following, the mole fraction is given in atomic percent (at% or %).

According to various embodiments, reference is made to physical vapor deposition (PVD) as an exemplary coating process, e.g., including a sputtering process, to be distinguished from chemical vapor deposition (CVD). In contrast to CVD, in PVD a solid material is first converted into the gas phase (also referred to as gaseous phase or vapor) and a layer is formed by means of this gas phase. In PVD, the gas phase of the target material can optionally be chemically reacted with a reactive gas to form a chemical compound that is built into or forms the layer. In the chemical reaction of PVD, two or more materials are thus brought together to form the chemical compound. In chemical vapor deposition, a gaseous starting compound (also known as a precursor or educt) is split into at least two reaction products, of which at least one reaction product is incorporated into the layer and, optionally, a reaction product is removed from the coating process as an excess (e.g. by means of a pump). Optionally, the CVD can be carried out using a plasma, in which the splitting of the precursor takes place.

A plasma can be formed using a so-called working gas (also referred to as a plasma-forming gas). According to various embodiments, the working gas may include a gaseous material that is inert, in other words, that participates in little or no chemical reactions. A working gas can, for example, be or be defined by the target material used and be or be adapted to it. For example, a working gas can include a gas or a gas mixture that does not react with the target material to form a solid or is even inert towards it. The working gas can have, for example, a noble gas (e.g. helium, neon, argon, krypton, xenon, radon) or several noble gases. The plasma can be formed from the working gas, which, for example, essentially causes the atomization of the target material. If a reactive gas is used, this can have a higher chemical reactivity than the working gas, e.g. with regard to the target material. In other words, the sputtered target material can react with the reactive gas (if any) faster (i.e., form more reaction product per time) than with the working gas (e.g., if it chemically reacts with the working gas at all). The reactive gas and the working gas can be supplied together or separately as a process gas (e.g. as a gas mixture), for example by means of the gas supply device.

According to various embodiments, a semiconductor material can be understood as a material that is electrically semiconductive in the pure (i.e., without impurities) and/or single-crystal state. For example, the semiconductor material may be an elemental semiconductor (such as silicon and germanium) or a compound semiconductor.

Electrically semiconductive can be understood as having an electrical conductivity (measured at room temperature and a constant electric field direction) in a range from about 10 ⁴ S/m to about 10 ^-4 S/m. Optionally, the semiconductor material can be contaminated or doped (introduction of foreign atoms). For example, the electrical conductivity can increase with an increasing degree of doping, so that the doped semiconductor material can also be electrically conductive (and not necessarily electrically semiconductive), for example. According to various embodiments, electrically conductive can be understood as having an electrical conductivity (measured at room temperature and a constant electric field direction) greater than about 10 ⁴ S/m, eg, greater than about 10 ⁶ S/m. The doped semiconductor material is also referred to herein as semiconductor material.

In contrast to a metal, for example, the semiconductor material cannot primarily have any free charge carriers, but these are only formed by heating. Electrically semiconducting can therefore exhibit that the electrical conductivity increases with increasing temperature, ie that a semiconductor material has a negative temperature coefficient.

A chemical element can be understood as a substance (also referred to as a pure substance) that can no longer be broken down into other substances using chemical methods. The smallest possible quantity of a chemical element is the atom. All atoms of a chemical element have the same number of protons in the nucleus (which is equal to the atomic number). The atoms of the same chemical element therefore agree in the structure of the electron shell and consequently also behave chemically in the same way.

In semiconductor technology, doping can be understood as the introduction of atoms of a dopant (also referred to as dopant) into the base material of a semiconductor (also referred to as semiconductor material). For example, a semiconductor layer may include or be formed from the semiconductor material.

The amount of atoms of the dopant (also referred to as doping atoms) introduced during this process is very small compared to the atoms of the base material (between 0.1 and 10000 ppm, i.e. parts per million). The dopant atoms can, for example, form imperfections in the semiconductor material and optionally change the electrical properties of the semiconductor material, i.e. the behavior of the electrons and thus the electrical conductivity. A low density of doping atoms can already bring about a very large change in the electrical conductivity.

If the electrical conductivity of the semiconductor material is changed, a distinction is made between p-doping (i.e. doping with positive polarity) and n-doping (i.e. doping with negative polarity). With p-doping, doping atoms are introduced that act as electron acceptors. With n-doping, doping atoms are introduced that act as electron donors.

To change the electrical conductivity of a semiconductor material made of silicon or germanium (or more generally a semiconductor material from the fourth main group), a dopant from the third main group can be used for p-doping, such as boron, indium, aluminum or gallium. To change the electrical conductivity of a semiconductor material made of silicon or germanium (or more generally a semiconductor material from the fourth main group), a dopant from the fifth main group, such as phosphorus, arsenic or antimony, can be used for n-doping.

However, the semiconductor material to be doped (e.g. the semiconductor layer) can also have or be formed from a semiconductor material other than silicon or germanium. For example, the semiconductor layer (e.g. on a wafer or another suitable carrier) or the semiconductor material to be doped can be manufactured from semiconductor materials of different types, which include a group IV semiconductor (e.g. silicon or germanium), a group III-V semiconductors (eg, gallium arsenide) or other types of semiconductors including, for example, group III semiconductors, group V semiconductors, or polymers. In various exemplary embodiments, the semiconductor material or the semiconductor layer (e.g. a substrate) is made from (e.g. undoped) silicon. As an alternative, any other suitable semiconductor material, e.g. for the semiconductor layer, can be used, e.g quaternary semiconductor compound material.

More generally speaking, the semiconductor material can have a value which, in the case of an element semiconductor (e.g. group III semiconductor or group IV semiconductor), corresponds to the value of the main group of the semiconductor, and in the case of a compound semiconductor, it corresponds to the mean value of the main groups of the components of the compound semiconductor. The compound semiconductors of the group III-V semiconductors can have the valency 4, for example. The III-V semiconductor gallium arsenide (GaAs) can, for example, be positively doped with a dopant such as carbon and tellurium negatively doped.

More generally speaking, the dopant may be of a main group whose value differs from, i.e. is smaller or larger than, the valency of the semiconductor material (e.g. around the value 1).

The doping may include increasing a concentration (also referred to as doping concentration) of the doping atoms in the semiconductor layer, eg to 1 doping atom/10 ⁷ semiconductor atoms (atoms of the semiconductor material) or more, eg to 1 doping atom/10 ⁶ semiconductor atoms or more, eg to 1 doping atom/10 ⁵ semiconductor atoms or more, eg to 1 doping atom/10 ⁴ semiconductor atoms or more, eg to 1 doping atom/10 ³ semiconductor atoms or more.

The dopant may include or be formed from at least the (i.e. exactly one or more than one) first chemical element.

Optionally, the doping can include activating the dopant introduced into the semiconductor layer, for example thermally. For this purpose, the semiconductor layer can be heated, for example to about 200° C. or more, for example to about 300° C. or more, for example to about 400° C. or more, for example to about 500° C. or more, for example to about 1000° C. or more more.

The semiconductor layer may generally be formed on a substrate, e.g., as (or part of) a coating of the substrate or may be integrated into the substrate. The substrate can be, for example, a semiconductor substrate (e.g. semiconductor wafer). For example, the substrate and the coating (e.g. the semiconductor layer) can differ from one another, e.g. in their crystal structure, their degree of doping (also referred to as degree of doping), their chemical composition, their semiconductor material, their thickness, or the like.

Reference is made herein to phosphorus as the second chemical element and silicon as the first chemical element by way of example. It can be understood that what has been described for silicon can also apply by analogy to another first chemical element or that what has been described for phosphorus can also apply by analogy to another second chemical element, e.g. for boron or arsenic. In the case of boron, the target can include or be formed from boron, for example.

1 illustrates a sputtering device 100 according to various embodiments in a schematic side view or cross-sectional view (looking at the axis of rotation 102a), wherein extensions along direction 105 are referred to as height and direction 103 are also referred to as transport direction, and direction 103 is transverse to the transport direction).

The sputtering apparatus 100 includes a magnetron 102 (e.g., a tubular magnetron or planar magnetron). A tube magnetron is discussed below as an exemplary magnetron 102 . What has been described for the tube magnetron can apply analogously to a planar magnetron as a magnetron 102 (also referred to as a plate magnetron) or as a double magnetron as a magnetron 102 .

The tube magnetron 102 can have a bearing device 1021 which is set up to support a tube-shaped magnetron cathode 102t (also referred to as a tube target or tube cathode) so that it can rotate. A tubular magnetron cathode 102t can, for example, have a tubular support (a so-called target base tube) on which (e.g. brittle and/or fragile) target material can be attached. Clearly, the target material can surround the target base tube in the form of a jacket. Alternatively, a tubular magnetron cathode 102t may include (e.g., a tube of target material) or be formed from a tubular configured target material (a so-called target tube).

The target material of the tubular magnetron 102 (also referred to as the first target material) can be, for example, a semiconductor material, e.g., silicon, e.g., doped silicon. The semiconductor material can have or be formed from a first chemical element as base material, in which a second chemical element is optionally introduced as a doping foreign component. For example, the target material of the tube magnetron 102 can be doped with the second chemical element. Doping ensures that the target material has greater electrical conductivity and can therefore be sputtered better.

For example, the first chemical element may include or be formed from silicon. For example, the second chemical element may include or be formed from phosphorus, boron, or arsenic.

For example, a concentration of the second chemical element (e.g., phosphorus) in the target material may be about 0.5 at% or less. For example, the target material may comprise silicon doped with phosphorus, with the phosphorus content being approximately 0.5 at% or less.

2 10 illustrates a sputtering apparatus 100 according to various embodiments in a schematic side view or cross-sectional view 200 (viewed along the axis of rotation 102a).

The magnetron 102 can be set up to provide a plasma during operation, which has migrated to the transport path 111, for example. In other words, between the transport path 111 and the target 102t of the magnetron 102, the plasma formation region 210 of the magnetron 102 can be arranged.

During operation of the sputtering device 100, a substrate 206 to be coated with the coating material can be transported past the tube magnetron 102 or at least be arranged close to the tube magnetron 102. The plasma formation region 220 of the tube magnetron 102 may face the substrate 206 or at least the path 111 along which the substrate 206 is transported (also referred to as transport path 111). This achieves the coating material atomized from the tube target 102t to the substrate 206 is emitted towards. For example, the substrate 206 may be coated (also referred to as coating the substrate) with the coating material atomized from the tube target 102t.

Generally speaking, the plasma formation region of a magnetron can be the region in which the plasma of the magnetron is formed. For sputtering, the formation of the plasma can be supported by means of a magnetic field, which can influence the ionization rate of the plasma-forming gas (e.g. the working gas). The magnetic field can be generated by means of a magnet arrangement (by means of a magnet system), whereby the magnetic field can be used, for example, to form a ring-shaped plasma formation area (plasma channel), i.e. a so-called race track, in which the plasma can form. For sputtering, the target material can be arranged between the plasma formation area and the magnet system, so that the target material can be penetrated by the magnetic field and the plasma formation area can run on the target material or on a target surface to be sputtered. The plasma formation area in each case borders on the surface to be sputtered (also referred to as the main surface) of a target.

The sputtering device 100 can optionally have a housing 222 in which the tubular magnetron 102 and/or the plate magnetron 104 are arranged.

According to various embodiments, the sputtering device 100 can have that the tube magnetron (eg its tube target) has or is formed from a silicon/phosphorus mixture (eg P:Si), eg having a concentration of phosphorus of 0.2 at% or less. The concentration of phosphorus of 0.2 at% can correspond to a concentration of 10 ²⁰ phosphorus atoms per cubic centimeter.

According to various embodiments, operating the sputtering apparatus 100 may include forming (also referred to as coating the substrate or sputtering) a layer comprising the coating material on a substrate.

According to various embodiments, the operation of the sputtering device 100 can include that a doping (eg phosphorus doping) of a formed layer is set and/or regulated, eg in a range from approximately 0.2 at% to approximately 2 at%. The concentration of phosphorus of 2 at% can correspond to a concentration of 10 ²¹ phosphorus atoms per cubic centimeter.

According to various embodiments, the operation of the sputtering device 100 can include that the doping (e.g. phosphorus doping) of the formed layer is set and/or regulated by means of a control device (e.g. implementing a control loop) which is set up, an actuator which has a rate at which the coating of the substrate takes place, influenced to drive. The control device can be set up, for example, to determine an operating point for the sputtering of a semiconductor material at which a charge carrier lifetime becomes maximum, based on a result of the changing of the rate.

3 10 illustrates a vacuum assembly 300 according to various embodiments in a schematic side view or cross-sectional view (viewed along the axis of rotation 102a) that the sputtering apparatus 100 comprises. The vacuum arrangement 300 can have a vacuum chamber 802 in which the sputtering device 100 is arranged.

The substrate 206 may be coated in the vacuum chamber 802 (also referred to as the processing chamber). The vacuum chamber 802 can be coupled to a pump system 804 (e.g. gas-conducting) in order to provide a negative pressure or a vacuum and can be set up so stably that it withstands the effects of the air pressure in the pumped-out state. When closed, the vacuum chamber 802 can, for example, be designed to be airtight, dust-tight and/or vacuum-tight. The pumping system (comprising at least one vacuum pump, e.g. a high-vacuum pump, e.g. a turbomolecular pump) can enable a part of the gas to be pumped out of the interior of the processing chamber.

According to various embodiments, the vacuum assembly 300 may include a gas delivery system 1716 (e.g., comprising one or more than one gas channel opening into the vacuum chamber). A working gas can be supplied to the vacuum chamber 802 by means of the gas supply system 1716 in order to form a working atmosphere in the vacuum chamber 802. The working pressure can be formed from an equilibrium of process gas, which is supplied by means of the gas supply system 1716 and withdrawn by means of the pump system 804.

According to various embodiments, the vacuum chamber can be set up in such a way that a pressure in a range from approximately 10 mbar to approximately 1 mbar (in other words rough vacuum) or less can be provided therein, for example a pressure in a range from about 1 mbar to about 10 ^-3 mbar (in other words fine vacuum) or less, for example a pressure in a range from about 10 ^-3 mbar to about 10 ^-7 mbar (in other words high vacuum) or less, for example a pressure of less as a high vacuum, eg less than about 10 ^-7 mbar.

If the substrate 206 is to be transported in the vacuum chamber 802 , the vacuum arrangement 300 can also have a transport device 302 .

The transport device 302 can have a multiplicity of transport rollers 302r, which are set up for transporting a plate-shaped substrate 206. The plate-shaped substrate 206 can be transported, for example, resting on the transport rollers 302r and/or placed in a substrate carrier (not shown). The plate-shaped substrate 206 can comprise a wafer or another semiconductor substrate, for example.

Alternatively, the transport device 302 can have an unwinding roller and a winding roller, which are set up to wind a strip-shaped substrate along the transport path 111 from the unwinding roller to the winding roller. Optionally, the transport device 302 can have a multiplicity of guide rollers, which are set up to deflect the transport path 111 one or more times, so that the substrate 206 is transported past the sputtering device 100 . A substrate in the form of a strip (tape substrate) can have or be formed from a film, a fleece, a strip and/or a woven fabric. For example, a strip-shaped substrate can have or be formed from a metal foil, a metal foil and/or a plastic film (polymer film).

4 illustrates a method 400 according to various embodiments in a schematic flowchart, e.g. for operating the sputtering device 100.

The method 400 includes, in 401, sputtering a target 102t (e.g. tubular target 102t) by means of a plasma.

The target 102t may include or be formed from the target material which is sputtered. The target material may include or be formed from a first chemical element which is, for example, doped, e.g., with a second chemical element. The coating material or the layer formed therefrom on the substrate 206 may include or be formed from the second chemical element and the first chemical element.

The method 400 optionally includes, in 405, coating a substrate 206 by sputtering the target 102t (e.g., tubular targets), e.g., by the coating material sputtered from the target. Sputtering the target may include sputtering the target material from the target 102t to provide the sputtered coating material. Coating the substrate may include transferring the coating material (comprising the target material) sputtered from the target 102t to the substrate 206 .

Coating the substrate 206 may include forming a layer on the substrate that includes or is formed from the coating material.

According to various embodiments, the substrate 206 may include or be formed from at least one of the following: a ceramic, a glass, a semiconductor (eg, an amorphous, polycrystalline, or single-crystalline semiconductor, eg, silicon), a metal (eg, aluminum, copper, iron, steel). , platinum, gold, etc.) a polymer (e.g. plastic) and/or a mixture of different materials, such as a composite material (e.g. carbon fiber-reinforced carbon, or carbon fiber-reinforced plastic).

The sputtering of the target 102t or the coating of the substrate 206 can take place in a vacuum, e.g. at the predefined pressure (also referred to as the working pressure). The vacuum can be provided in the vacuum chamber 802 .

The method 400 optionally includes, in 407, supplying the plasma with a working gas. The working gas can include or be formed from an inert gas, for example. The working gas can include or be formed from krypton, for example. This achieves that the atomization of the coating material takes place by means of krypton, which affects the electrical properties of the layer, as will be described in more detail later.

The sputtering of the target 102t or the coating of the substrate 206 can only take place in the working gas, for example at the working pressure. The working gas can be provided at the working pressure in a vacuum chamber, as will be described in more detail later. The working pressure is, for example, in a range from about 10 ^-2 mbar to about 10 ^-4 mbar or less.

Optionally, the layer formed on the substrate can be a semiconductor layer, for example a doped semiconductor layer.

Optionally, the layer formed on the substrate can be amorphous. For example, the atoms of the semiconductor layer (ie the semiconductor atoms) cannot form an ordered structure but an irregular pattern and only have short-range order, but not long-range order.

A first application example has that the target material has a dopant as the second chemical element with which the target material is doped. In other words, the second chemical element can be the dopant.

A second application example comprises that the substrate coated with the coating material is heated (also referred to as heat treatment), for example by means of a heating device. This favors the dopant being activated. If the target material has the dopant as a second chemical element, the heating may favor the coating material being electrically altered by the dopant (also referred to as activating the doping).

A third application example has that the target material has phosphorus (P) as the second chemical element. Phosphorus can be used as a dopant for the target material, for example when the target material comprises or is formed from silicon. Clearly, the provided sputtering device can make it easier to provide a coating material that has phosphorus and silicon, or to coat the substrate with a layer that has phosphorus-doped silicon. Phosphorus cannot be provided as a tubular target. Phosphorus-doped silicon, for example, can only be provided with difficulty or not at all as a tube target. For example, the cost of a tubular phosphorus-doped silicon target is greater than the cost of a phosphorus-doped silicon planar target. According to various embodiments, it is clearly achieved that the silicon of the tube magnetron can be mixed with the phosphorus of the planar magnetron. For example, the chemical composition of the coating material or the layer can show that the proportion of P (ie the phosphorus concentration) is greater than 0.5 at% and/or less than 50 at%, eg greater than 1 at% and/or less is than 10 at%.

A fourth application example has that the target material is formed essentially from silicon.

A fifth application example has that the target material of the fourth application example has a concentration of phosphorus of less than 0.01 at%.

A sixth application example shows that a tube target 102t made of a silicon/phosphorus mixture is coated with phosphorus and/or optionally with silicon by means of the planar magnetron. The tubular target 102t or the silicon/phosphorus mixture can have a phosphorus concentration of less than approximately 0.5 at%, for example less than approximately 0.2 at%.

The sixth application example has, for example, that the tube target 102t is sputtered from a silicon/phosphorus mixture with a low phosphorus concentration (for example such that the tube target is electrically conductive for DC sputtering) and a layer is deposited on the substrate.

The phosphorus concentration of the coating material or the coating of the tubular target with phosphorus can be set and/or regulated by controlling the plasma power of the tubular magnetron and/or the planar magnetron. Alternatively or additionally, the phosphorus concentration of the layer formed on the substrate (e.g. a sputtered aSi:P layer) can be set and/or regulated by controlling the plasma power of the tubular magnetron and/or the planar magnetron.

The phosphorus concentration of the coating material or the layer can be increased, for example, by increasing the plasma power of the planar magnetron. If the plasma power of the tube magnetron is increased (which increases its sputtering rate), the phosphorus concentration of the coating material or layer can be reduced. This can be counteracted by tracking the plasma power of the planar magnetron. Examples of additional variables that influence the phosphorus concentration of the coating material or the layer can include: the speed of the tube target and the working pressure.

Examples of the controlled variable (e.g. measured variable) for setting and/or controlling the phosphorus concentration include: an optical emission of the plasma of the tube magnetron (e.g. its spectrum), an X-ray fluorescence (XRF) of the layer formed on the substrate 206 (e.g. its spectrum). The layer formed on the substrate 206 can be excited to X-ray fluorescence, for example. The recorded spectrum can have, for example, a first intensity of the X-ray fluorescence characteristic of phosphorus and a second intensity of the X-ray fluorescence characteristic of silicon. A ratio of the first intensity to the second intensity can thus also be used as the controlled variable. Alternatively or additionally, a ratio of P to Si be used, which is determined based on the X-ray fluorescence, for example based on the ratio of the first intensity to the second intensity.

5 FIG. 5 illustrates a semiconductor device 500 according to various embodiments in a schematic side view or cross-sectional view (viewed along the transport direction), which is produced by means of the sputtering device 100 or by means of the method 400. FIG.

The semiconductor device 500 can have an n-doped silicon wafer as the substrate 206 . The semiconductor component 500 can also have a layer stack 502 with which the substrate is coated on one side or on both sides. The layer stack 502 may include, for example, a first layer of silicon nitride (SiN) and a second layer of amorphous silicon (aSi), e.g., 100 nanometers (nm) thick, disposed between the substrate 206 and the first layer. The first layer can optionally also be omitted.

The semiconductor component 500 can optionally be a so-called tunnel oxide passivated contact solar cell, also referred to as a TOPCon (Tunnel Oxide Passivated Contact) solar cell, or at least its working sample. The semiconductor device 500 can then have a tunnel oxide layer between the layer stack 502 and the substrate 206, for example with a thickness of 1.5 nanometers. The working sample can be used, for example, to determine the lifetime of the charge carriers (then also referred to as lifetime sample), as will be explained in more detail later.

The second layer of amorphous silicon (aSi) can be produced using the sputtering device 100 or using the method 400 as described above. For example, the second layer can be a phosphorus-doped amorphous silicon layer.

6 FIG. 12 illustrates a semiconductor device 600 according to various embodiments in a schematic side view or cross-sectional view (viewed along the transport direction), which is produced by means of the sputtering device 100 or by means of the method 400. FIG.

The semiconductor device 600 can have a p-doped silicon wafer as the substrate 206 . The semiconductor component 600 can furthermore have a first layer stack 502, with which the substrate is coated on the underside, and a second layer stack 602, with which the substrate is coated on the top side. The first layer stack 502 may include, for example, a first layer of metal and the second layer of boron-doped amorphous silicon (B:aSi), e.g., 50 nanometers (nm) thick, disposed between the substrate 206 and the first layer.

The second layer stack 602 may include, for example, an additional first layer of silicon nitride (SiN) and an additional second layer of n-doped silicon (n-Si) disposed between the substrate 206 and the additional first layer.

The semiconductor component 600 can have one or more than one contact-connection 604, which penetrates through the second layer stack 602 and/or contacts a highly n-doped region embedded in the substrate.

The semiconductor device 600 can optionally be a tunnel oxide passivated contact solar cell. Then the semiconductor device 600 between the first layer stack 502 and the substrate 206 can have a tunnel oxide layer made of silicon oxide, e.g. of 1.5 nanometers thickness.

The additional second layer of n-doped silicon (n-Si) can be produced by means of the sputtering device 100 or by means of the method 400 as described above. For example, the additional second layer of n-doped silicon (n-Si) may be a phosphorus-doped amorphous silicon layer.

7 illustrates the method 400 according to various embodiments 700 in a schematic flowchart, for example for operating the sputtering device 100, wherein the to 4 Described may apply by analogy.

The method 400 includes, in 701, sputtering a semiconductor material (e.g., as a target material) using a plasma. The semiconductor material can be provided, for example, by means of a tube target 102t and/or by means of at least one planar target, so that the method 400 includes the tube target 102t or the at least one planar target being sputtered 401 .

As described above, the semiconductor material can be part of the coating material, which optionally has a dopant. The coating material can, for example, comprise a mixture (also referred to as a mixture of substances) or a compound (also referred to as a chemical compound) which comprises the semiconductor material and the dopant (e.g. phosphorus).

For example, the target material may include the dopant (e.g., phosphorus) such that the semiconductor material is or becomes doped.

According to various embodiments, different target materials do not necessarily have to be sputtered, or the sputtering device does not necessarily have to have a number of targets. For example, the semiconductor material can be sputtered from a tube target or a planar target, with the semiconductor material optionally being doped.

The method 400 includes, in 405, coating a substrate 206 with at least the sputtered semiconductor material. For example, the semiconductor material that is sputtered may be doped, e.g., with phosphorous. For example, sputtering the semiconductor material may include sputtering the target material from the tube target 102t. Coating the substrate may include, for example, transferring the coating material (comprising the semiconductor material and optionally the dopant) sputtered from the tube target 102t to the substrate 206 .

Coating the substrate 206 may include forming a layer on the substrate that includes or is formed from the coating material.

The method 400 optionally includes, in 407, supplying the plasma with a working gas that includes or is formed from krypton. This achieves that the plasma with which the semiconductor material is sputtered contains krypton. Supplying the plasma with a working gas can include supplying the working gas to the plasma. For example, high-purity krypton (e.g., having more than 99.99 at% krypton) can be continuously supplied to the plasma, e.g., from a gas reservoir.

The use of a plasma containing krypton for sputtering a semiconductor material is explained in more detail below.

8th FIG. 8 illustrates a diagram 800 according to various embodiments, in which the electrical properties of different working samples (also referred to as samples for short) are shown, each sample having a substrate coated by means of the sputtering apparatus 100 or by means of the method 400, respectively. The substrate 206 can be a p-doped wafer, for example.

Axis 801 plots the implied open circuit voltage (iVoc) as a representative of the charge carrier lifetime of the sample. The larger the iVoc, the longer the service life of the charge carriers. The number of the sample (e.g. a lifetime sample or a solar cell) whose open-circuit voltage was determined is plotted on axis 803 .

The open circuit voltage is the maximum voltage produced by the sample at zero current. The open circuit voltage corresponds to the magnitude of the forward voltage due to the biasing of the solar cell junction with the charge carriers generated by the light. To determine the open circuit voltage, the coated substrate can be exposed by means of a flash and the conductivity of the sample can be recorded. Based on the conductivity of the sample over time, the lifetime of the charge carriers and the implied open circuit voltage can be determined.

Shown is the open circuit voltage for sample group 1 (PG1), for sample group 2 (PG2) and sample group 3 (PG3). In sample group 1, argon was used as the working gas to form the plasma by which the semiconductor material was atomized (sputtered). In sample group 2, helium was used as the working gas to form the plasma by which the semiconductor material was atomized (sputtered). In sample group 3, krypton was used as the working gas to form the plasma by which the semiconductor material was atomized (sputtered).

Forming a doped aSi layer by sputtering for use in a TOPCon configuration allows for good scalability and avoidance of the toxic gases that have to be used in PECVD. According to various embodiments, it was recognized that on the one hand the sputtering conditions have a great influence on the lifetime of the charge carriers (also referred to as charge carrier lifetime), but on the other hand also the oxygen built into the aSi layer parasitically.

According to various embodiments, krypton is used as the working gas. Sputtering using krypton (Kr) can achieve a significantly longer carrier lifetime than using helium or argon. It was also recognized that cell procurors have a significantly better passivation effect on the layers sputtered with krypton, which, for example, come close to the comparison samples produced by means of PECVD.

When forming such an aSiP layer by means of sputtering, the specific dynamic rate (DDR) could finally be determined as a meaningful process parameter from a large number of tests in which different manipulated variables such as plasma power, working pressure, target-to-substrate distance (TSD) were varied be identified, which allows the iVoc to be optimized. This is explained below.

9 FIG. 9 illustrates a graph 900 according to various embodiments, in which the properties of various samples that were produced using the sputtering apparatus 100 or using the method 400 are shown. The implied open circuit voltage (iVoc) is plotted on axis 801 as a representative of the lifetime of the charge carriers. Coating rate is plotted on axis 803, ie the rate at which the substrate was coated. The oxygen content of the sample is plotted on axis 805 . The samples had n-doped wafers coated with aSiP, for example, and were annealed after coating.

The coating rate is given as a so-called specific dynamic rate (DDR), which simplifies the comparison of different manufacturing conditions. The DDR indicates the average coating rate as a volume growth rate (e.g. rate of thickness growth times coated area) normalized to the plasma power (e.g. in angstrom square millimeters / (watts second)).

The coating rate is a function of the following variables: the plasma power, the working pressure and the distance of the substrate from the target (also known as TSD). The coating rate was varied by changing one or more of these variables.

Based on the dependency of the iVoc and the oxygen content, it can be seen that the iVoc increases with a decreasing coating rate. However, the trend is only present as long as clearly little oxygen is built into the layer. Because it can be seen that the falling coating rate also favors the incorporation of oxygen (also referred to as oxygen incorporation) into the layer.

Oxygen is incorporated into the layer during sputtering under certain process conditions when it is formed. Basically, this can be counteracted by making the working atmosphere particularly clean. This can be achieved, for example, by the base pressure of the vacuum arrangement being particularly low. The base pressure is the lowest pressure that can be generated in the vacuum chamber and thus represents the maximum level of possible contamination of the working atmosphere. For example, the working atmosphere may be greater than 90 at% (e.g., greater than 99 at%) krypton.

The rate of oxygen incorporation increases with increasing working pressure, increases with increasing TSD, and decreases substantially linearly with increasing plasma power. However, the incorporation of oxygen cannot be prevented even at the lowest possible base pressure.

The comparison between PG3 and PG1 shows that sputtering using krypton continues the trend of increasing iVoc with decreasing coating rate and thus enables a higher iVoc than sputtering using argon. Clearly, sputtering using krypton inhibits the incorporation of oxygen, so that sputtering can be carried out at a lower coating rate.

10 FIG. 10 illustrates a diagram 1000 according to various embodiments, in which the properties of various samples that were produced using the sputtering apparatus 100 or using the method 400 are shown. The surface resistance of the substrate is plotted on axis 807 as a representative of the conductivity of the doped aSi layer. Coating rate is plotted on axis 803, ie the rate at which the substrate was coated. The oxygen content of the sample is plotted on axis 805 . The base resistance of the wafer is approximately at point 807b, ie approximately in the area of the sheet resistance of PG1. This shows that krypton also has a very positive influence on the sheet resistance after annealing. While hardly any electrically conductive layers are produced with argon, layers sputtered with krypton (see PG3) are much more conductive.

11 FIG. 1100 illustrates a diagram 1100 according to various embodiments, in which the properties of different samples that were produced by means of the sputtering apparatus 100 or by means of the method 400 are shown. The oxygen content of the layer is plotted on axis 809 . A process variable is plotted on axis 813, which represents the product of the working pressure, a function of the plasma power and the TSD.

For PG1, the dashed line shows the case of high base pressure (illustratively a contaminated vacuum) and the solid line shows the case of low base pressure (illustratively a vacuum that is as clean as possible). Despite a difference of almost two orders of magnitude, the base pressure has hardly any influence on the oxygen incorporation. On the other hand, the difference between argon and krypton as the working gas is clearer over the selected process variable (less oxygen incorporation with Kr), albeit not very large. If this data situation is presented differently, however, this difference is clearer, as will be explained below.

12 FIG. 1200 illustrates a diagram 1200 according to various embodiments, in which the properties of different samples, which are produced by means of the sputtering device 100 or by means of the Method 400 are shown. The oxygen content of the layer is plotted on axis 805 . The coating rate is plotted on axis 803 . The coating rate is given as specific dynamic rate (DDR). For PG1, the dashed line shows the case of high base pressure (illustratively a contaminated vacuum) and the solid line shows the case of low base pressure (illustratively a vacuum that is as clean as possible) for comparison.

As can be seen, the higher base pressure (also known as worse residual gas pressure) has less of an impact on oxygen incorporation than replacing argon as the working gas with krypton as the working gas. A significantly larger DDR range is obtained for krypton as the working gas, in which the oxygen incorporation remains low. This can be exploited when forming a doped aSi layer by sputtering. For example, the aSi layer can be deposited without elevated temperature, e.g. at standard temperature, and/or subsequently annealed.

According to various embodiments, a semiconducting target can be sputtered using a plasma (also referred to as sputtering), the plasma comprising krypton, and a substrate can be coated using the coating material sputtered from the target.

Coating the substrate may include, for example, forming a semiconductor layer, e.g., a doped and/or amorphous semiconductor layer, e.g., a doped and/or amorphous silicon layer.

Coating a substrate may include, for example, forming a passivating and electrically conductive layer, e.g., in a tunnel oxide passivated contact solar cell.

As in 9 explained, it was recognized that as the specific dynamic rate (DDR) decreases, the iVoc increases after annealing the formed layer up to a maximum, from which significant proportions of oxygen are incorporated into the layer. The built-in oxygen causes the iVoc to drop. As in 10 explained, after annealing a resistance reduction of the wafer-layer composite can only be achieved by sputtering with krypton. However, the electrical resistance can increase as the oxygen concentration in the layer increases. When sputtering with argon, the base resistance of the wafer is mainly reproduced, which means that the layer formed does not contribute to the conductivity of the layer-substrate composite even after annealing. Therefore, sputtering with krypton leads to better controllability of the sputtering process with a wider range of parameters and to the production of an electrically conductive layer after tempering.

In principle, it can be understood that the influence of krypton on the electrical properties of the layer formed, as described herein, can be changed continuously. For example, the working gas can also consist of a mixture of krypton and another inert gas (e.g. argon) if the need arises.

According to various embodiments, the method may include forming an in situ doped aSi layer with good passivation effect (iVoc after anneal) as well as good conductivity (Rs after anneal).

13 illustrates the method 400 according to various embodiments 1300 in a schematic flow chart, for example for operating the sputtering device 100, wherein the to 4 and or 7 Described may apply by analogy.

The method 400 includes, in 1301, changing a rate at which the coating of the substrate occurs (also referred to as coating rate); and in 1303, determining an operating point for sputtering a semiconductor material at which a carrier lifetime becomes maximum based on a result of changing the rate.

Changing the coating rate may include changing the plasma power, the working pressure and/or the distance of the substrate from the target (e.g. tubular target).

The result of changing the rate can be detected, for example, by optically and/or electrically detecting a coated substrate, which is optionally further annealed (heat treated). Electrically sensing the substrate may include sensing an electrical property of the substrate representing charge carrier lifetime. The electrical property of the substrate can include, for example, an electrical resistance of the substrate and/or the time profile of the electrical resistance of the substrate. The course of the electrical resistance over time can be recorded, for example, after the substrate has been irradiated by means of a flash of light.

Determining an operating point may include coating a plurality of substrates, each of which is coated at a different operating point, and determining the result of changing the rate for each substrate. On the basis of the pairs obtained in this way from the operating point and the result of the changing of the rate (eg electrical property of the substrate), that operating point can be selected whose result of the changing of the rate satisfies a predefined criterion. The criterion can have, for example, that the electrical property of the substrate represents a maximum charge carrier lifetime or is at least above a threshold.

Various examples are described below, which relate to those described above and shown in the figures.

Example 1 is a method comprising: sputtering a (e.g. doped) semiconductor material (which is e.g. part of a tubular target of the tubular magnetron) and/or a semiconducting target by means of a plasma, the plasma comprising or being formed from krypton; Coating of a substrate by means of the sputtered semiconductor material or by sputtering of the semiconducting target.

Example 2 the method according to example 1, wherein the semiconductor material is doped (e.g. with a dopant), or wherein the semiconductor material is part of a mixture or chemical compound, wherein the mixture or chemical compound is further doped (e.g. with a dopant).

Example 3 The method according to example 1 or 2, wherein the substrate has an additional semiconductor material and/or is doped (e.g. with a doping type or conductivity type opposite to the semiconductor material).

Example 4 The method according to any one of Examples 1 to 3, wherein the substrate is a solar cell substrate.

Example 5 The method according to any one of Examples 1 to 4, further comprising: forming a solar cell using the substrate.

Example 6 The method according to any one of Examples 1 to 5, wherein a layer formed by means of the sputtered semiconductor material has a smaller electrical resistivity (e.g. sheet resistance) than the substrate and/or has an electrical resistivity (e.g. sheet resistance) sheet resistance that is smaller than about 600 ohms, eg about 500 ohms, eg about 450 ohms, eg about 200 ohms.

Example 7 The method of any one of Examples 1 to 6, wherein the coated substrate has an open circuit voltage of greater than about 0.6 volts, eg, greater than about 0.61 volts, eg, greater than about 0.62 volts, , eg, greater than about 0.63 volts, e.g. about 0.64 volts, e.g. about 0.65 volts, e.g. about 0.66 volts, e.g. about 0.67 volts, e.g. about 0.68 volts, e.g. about 0, 69 volts, for example about 0.7 volts, for example about 0.73 volts.

Example 8 The method according to any one of Examples 1 to 7, wherein a layer formed by means of the sputtered semiconductor material has an oxygen concentration which is less than about 10 at%, eg less than about 7.5 at%, eg less than about 5 at%, eg than about 2.5 at%, e.g. as about 1 at%, e.g. as about 0.5 at%, e.g. as about 0.25 at%, e.g. as about 0.1 at%, e.g. as about 0.05 at% , eg as about 0.01 at%, eg as about 0.001 at%.

Example 9 The method according to any one of Examples 1 to 8, wherein a layer formed by means of the sputtered semiconductor material has a lower electrical resistivity than the substrate.

Example 10 The method according to any one of Examples 1 to 9, wherein the coating comprises forming an amorphous layer on the substrate, for example wherein the amorphous layer comprises or is formed from the semiconductor material.

Example 11 The method of any one of Examples 1 to 10, wherein the semiconductor material is inorganic and/or doped.

Example 12 The method according to any one of Examples 1 to 11, wherein the semiconductor material is electrically conductive or electrically semiconductive.

Example 13 The method according to any one of Examples 1 to 12, wherein the semiconductor material comprises or is formed from silicon, or wherein the semiconductor material comprises or is formed from doped silicon.

Example 14 The method according to any one of Examples 1 to 13, wherein the coating comprises forming a semiconductor layer on the substrate comprising or formed from the semiconductor material.

Example 15 The method according to any one of Examples 1 to 14, further comprising: forming a tunnel oxide layer on the substrate, e.g., adjacent to the semiconductor layer.

Example 16 The method according to any one of Examples 1 to 15, further comprising: supplying the plasma with krypton (eg by supplying krypton gas) and/or argon.

Example 17 The process according to any one of Examples 1 to 16, wherein the plasma has more krypton than argon.

Example 18 The method according to any one of Examples 1 to 17, wherein the plasma is exposed to a vacuum such that a change (e.g. decrease and/or increase) in pressure (e.g. working pressure) results in a decrease in a rate at which coating of the substrate Oxygen is incorporated (into the layer), causes (e.g. with the same residual gas pressure and the same coating rate).

Example 19 the method according to any one of examples 1 to 18, wherein the plasma is subjected to a vacuum such that a change (e.g. reduction and/or increase) in pressure (e.g. working pressure) causes incorporation of oxygen during coating (into the layer) favored (e.g. with the same residual gas pressure and the same coating rate).

Example 20 The method according to one of Examples 1 to 19, the plasma being supplied with a working gas which has a concentration of krypton such that a reduction in the concentration of krypton promotes the incorporation of oxygen during coating (into the layer) (e.g at the same coating rate) and/or that replacing krypton with argon promotes the incorporation of oxygen during coating (into the layer) (eg at the same coating rate).

Example 21 the method according to any one of Examples 1 to 20, wherein the plasma is supplied with a working gas having a concentration of krypton (eg more than 50 at% or 90 at%) such that a reduction in the concentration of krypton Increasing a rate at which oxygen is incorporated (into the layer) when the substrate is coated (eg at the same coating rate).

z.B. als ungefähr $$1300\text{Angstr}\ddot{\text{o}}\text{m}\cdot \text{Quadratmillimeter / (Watt}\cdot \text{Sekunde)}\text{,}$$

z.B. als ungefähr $$1200\text{Angstr}\ddot{\text{o}}\text{m}\cdot \text{Quadratmillimeter / (Watt}\cdot \text{Sekunde)}\text{,}$$

z.B. als ungefähr $$1000\text{Angstr}\ddot{\text{o}}\text{m}\cdot \text{Quadratmillimeter / (Watt}\cdot \text{Sekunde)}$$

als ungefähr $$\text{800 Angstr}\ddot{\text{o}}\text{m}\cdot \text{Quadratmillimeter / (Watt}\cdot \text{Sekunde)}\text{.}$$

800 Angström · Quadratmillimeter / (Watt · Sekunde).Example 22 The method according to any one of Examples 1 to 21, wherein the coating of the substrate occurs at a rate (also referred to as the coating rate, eg the specific dynamic coating rate) which is less than about $$1500\text{afraid}\ddot{\text{O}}\text{m}\cdot \text{Square millimeters / (Watt}\cdot \text{Second)}\text{,}$$

eg as approximately $$1300\text{afraid}\ddot{\text{O}}\text{m}\cdot \text{Square millimeters / (Watt}\cdot \text{Second)}\text{,}$$

eg as approximately $$1200\text{afraid}\ddot{\text{O}}\text{m}\cdot \text{Square millimeters / (Watt}\cdot \text{Second)}\text{,}$$

eg as approximately $$1000\text{afraid}\ddot{\text{O}}\text{m}\cdot \text{Square millimeters / (Watt}\cdot \text{Second)}$$

than approximately $$\text{800 fear}\ddot{\text{O}}\text{m}\cdot \text{Square millimeters / (Watt}\cdot \text{Second)}\text{.}$$

800 angstroms square millimeters/(watts second).

Example 23 The method according to any one of Examples 1 to 22, further comprising: changing a rate at which the coating of the substrate occurs; determining an operating point for sputtering the semiconductor material at which a carrier lifetime becomes maximum based on a result of changing the rate.

Example 24 is a method (e.g. method according to any one of Examples 1 to 23) comprising: changing a rate at which coating of a substrate occurs; Determination of an operating point for the sputtering of a semiconductor material at which a charge carrier lifetime becomes maximum, based on a result of changing the rate, for example changing the coating rate having the plasma power, the working pressure and/or the distance of the substrate from the target (e.g. tube target ) to change.

Example 25 is a semiconductor device (e.g., a solar cell, e.g., a tunnel oxide passivated contact solar cell) comprising: a semiconductor substrate; a silicon layer formed by sputtering in or over the semiconductor substrate, the silicon layer being doped with a dopant, wherein a concentration of the dopant in the silicon layer is greater than about 0.5 at% and/or less than about 50 at% than about 0.75 at% and/or less than about 10 at%.

Example 26 is using krypton to form a plasma when performing a sputtering process by which a, e.g., doped, semiconductor (e.g., silicon) layer is formed.

Claims (18)

A method (400) comprising: • sputtering (401) a semiconductor material by means of a plasma, the plasma comprising krypton; • Coating (405) a substrate with the sputtered semiconductor material. Method (400) according to claim 1 , where the semiconductor material is doped. Method (400) according to claim 1 or 2 , wherein the substrate has an additional semiconductor material and / or is doped. Method (400) according to claim 3 , wherein the substrate is doped with a conductivity type opposite to that of the semiconductor material. Method (400) according to any one of Claims 1 until 4 , further comprising: forming a solar cell using the substrate. Method (400) according to any one of Claims 1 until 5 , wherein the coating comprises forming an amorphous layer on the substrate comprising the semiconductor material. Method (400) according to claim 1 until 6 , wherein a layer formed by means of the sputtered semiconductor material has a smaller electrical resistivity than the substrate. Method (400) according to any one of Claims 1 until 7 , wherein the semiconductor material comprises silicon. Method (400) according to any one of Claims 1 until 8th , wherein the semiconductor material comprises doped silicon. Method (400) according to any one of Claims 1 until 9 , further comprising: forming a tunnel oxide layer on the substrate. Method (400) according to any one of Claims 1 until 10 , further comprising: supplying the plasma with krypton. Method (400) according to any one of Claims 1 until 11 , where the plasma has more krypton than argon. Method (400) according to any one of Claims 1 until 12 , wherein the plasma is exposed to a vacuum in such a way that an increase in the working pressure favors the incorporation of oxygen during coating. Method (400) according to any one of Claims 1 until 13 , wherein the plasma is supplied with a working gas which has a concentration of krypton such that a reduction in the concentration of krypton promotes the incorporation of oxygen during coating. Method (400) according to Claim 14 , where the concentration of krypton is more than 50 at%. Method (400) according to any one of Claims 1 until 15 further comprising: • changing (1301) a rate at which the coating of the substrate occurs; • determining (1303) an operating point for sputtering a semiconductor material at which a carrier lifetime becomes maximum based on a result of changing the rate. A method (400) comprising: • changing (1301) a rate at which coating of a substrate occurs; • determining (1303) an operating point for sputtering a semiconductor material at which a carrier lifetime becomes maximum based on a result of changing the rate. Using krypton to form a plasma when performing a sputtering process by which a semiconductor layer is formed.

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