DE2711365A1 - SEMI-CONDUCTOR ARRANGEMENT WITH SCHOTTKY BORDER LAYER - Google Patents

Description

Dn.-Ing. Reiman König ■ Dipl.-Ing. Klaus Bergen Cecilienallee 76 Λ Düsseldorf 3O Telephone 45 2008 Patent Attorneys

March 14, 1977 31 308 B

RCA Corporation, 30 Rockefeiler Plaza, New York , NY 10020 (V.St.A.)

"Semiconductor device with Schottky boundary layer"

The present invention relates to semiconductor arrangements, in particular to those with a Schottky boundary layer, as they are used, for example, in photo voltage and current rectifier arrangements, in which amorphous silicon produced by glow discharge in silane is used.

Photo voltage devices such as solar cells and photo detectors are able to capture light from the area, for example converting infrared light to ultraviolet light into usable electrical energy. A problem in the field of solar cells is that because of the cost of the solar cell-derived electrical Energy this process is often not competitive with other types of generation. One of the biggest items of expenditure in solar cell production is the price of the semiconductor material used in the solar cells. Naturally the more semiconductor material is required, the higher the price of a solar cell. A decrease of the required semiconductor material for photodetector arrangements would also reduce their costs. If that same semiconductor material has current rectifying properties in the dark, so it could too in semiconductor arrangements such as diodes, use.

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It has now been found that the base bodies of the photo voltage and current rectifier assemblies are very thin can be made using amorphous silicon, which was produced by glow discharge in silane. A However, the problem that arises in some of these arrangements is making an ohmic contact on such manufactured, amorphous silicon.

The invention is based on the object of a semiconductor arrangement to create using amorphous silicon in which its advantages are fully retained, the but at the same time enables a good ohmic contact to the amorphous silicon.

The task is according to the invention by the kenazeiohnenden Part of claim 1 and claims 7 and 10 specified features solved »Further embodiments of the invention are specified in the referenced subclaims.

In the drawings, exemplary embodiments of the present invention are shown, on the basis of which the invention is explained in more detail is explained. Show it:

1 shows a cross section of a first exemplary embodiment of a semiconductor device with a Schottky boundary layer according to the invention;

FIG. 2 is a graph showing the absorption coefficient of single crystal silicon compared to amorphous silicon produced by glow discharge, specifically in the visible light range; FIG.

3 shows a schematic representation of a first device for the production of amorphous silicon by means of a glow discharge in silane;

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4 is a schematic representation of a second device for the production of amorphous silicon by glow discharge in silane;

Fig. 5 shows a cross section of a second exemplary embodiment of a semiconductor device with a Schottky boundary layer according to the invention.

In FIG. 1, a first exemplary embodiment of the semiconductor arrangement according to the present invention is denoted by 10. The semiconductor device 10 has a substrate 12 made of a material with good electrical conductivity properties »Typical materials with these properties are aluminum, chromium, stainless steel, niobium, tantalum, iron and
Indium tin oxide on glass.

A base body 13 made of amorphous silicon, which was produced by glow discharge in silane SiH, is applied to a surface of the substrate 12. The deposition method known to those skilled in the art involves electrical discharge by gas at relatively low pressure, for example around 5 torr or less, in a partially evacuated chamber. A glow discharge is characterized by several areas of diffuse, glowing glow, for example the positive glow column near the anode and the negative glow area between anode and cathode, and a voltage drop in the vicinity of the cathode,
which has a much higher potential than the ionization potential of the gas, for example the Crookes dark room area.

Amorphous material is material that has no order about it
larger areas with respect to the periodicity of the matrix
having. Amorphous silicon produced by glow discharge

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in silane, SiH-, has an order in a small area of not more than 20 Å. The lack of order over larger areas in amorphous, Silicon produced by glow discharge in silane can be detected by X-ray or electron diffraction will.

The body 13 has a first layer 14 made of amorphous silicon, which was produced by glow discharge in a mixture of silane and doping gas. The first layer 14 has an ohmic contact with the substrate 12, a first interface 15 lying between the two. A second layer 16 made of amorphous silicon within the body 13 is applied to the first layer 14 on the side facing away from the substrate 12. The second layer 16 was formed by a glow discharge in silane, SiH ,,, typically by a glow discharge in essentially pure silane. Since the glow discharge takes place in essentially pure silane, one would assume that the second layer 16 is undoped, but it has been found that this second layer 16, although made in pure silane, is lightly n-doped, for example when deposited on a Surface that has been heated to a temperature of more than 100 ^{° C.} The first and second layers 14 and 16, respectively, are of the same conductivity type. The doping concentration of the first layer 14 preferably decreases in such a way that it has a maximum at the interface 15 and decreases to an insignificant concentration at the interface of the first layer 14 with the second layer 16. Although the first layer preferably has a stepped or decreasing doping concentration, doping concentrations are also used with the present invention for reasons which will be explained below

which are uniform throughout the entire layer 14.

The amorphous silicon of the first and second layers 14 and 16 is produced by a glow discharge in silane plus one suitable doping gas is formed for the layer 14, and can thereby be distinguished from other amorphous silicon be that it has the kinetic properties of an average density of states of the order of 10 / ClYr or below. The average Density of states is determined by recording the ratio of 1 to the squared capacitance (1 / C) as Function of the voltage prevailing on the silicon semiconductor arrangement. From the form of this record, professionals can determine the average density of states. In the production of amorphous silicon by glow discharge in silane the drift mobility for electrons is 10 ^ cm / V-seco or more. The drift mobility of the electrons is measured by known measures, applying light pulses or electron beam pulses to the biased Can impinge semiconductor device and the subsequent electron flow generated by the pulses is through

tracked a sampling system. From measurements of the photoconductivity it has also been estimated that the Order of magnitude of the lifetime of the electrons of amorphous silicon generated by the glow discharge in silane

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on the order of 10 see. lies. Nevertheless, it can be assumed that amorphous silicon produced by glow discharge in silane, with an electron life of the order of 10 seconds or more, also has good electrical properties.

The first layer 14 is typically between 100 and approximately 0.5 micrometers thick, the second layer 16 between about 1/2 and 1 micrometer thick.

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On the surface of the second layer 16 facing away from the first layer 14, there is a metal film 18 at an interface 20 attached. The metal film 18 is at least semi-transparent to solar radiation when the arrangement to be used as a solar cell, and is made of metal with good electrical conductivity and high Normal potential, for example greater than 4.5 eV, i.e. a noble metal, assuming that the second Layer 16 is η-conductive. Metals with good electrical conductivity and high normal potential, i.e. a noble one Metal are, for example, gold, silver, platinum, palladium, rhodium, iridium or chromium. The metal film 18 can be made of consist of a single metal layer or of multiple layers. If the metal film 18 consists of several layers consists, a first layer of platinum could rest on the second layer 16, and a second layer on the first platinum layer could be gold or silver in order to achieve good electrical conductivity. As previously determined, in the case of a solar cell, the metal film 18 is at least semi-transparent to solar radiation, and for this purpose, since it is a metal, it should be about 100 Å thick.

The first layer is usually η-conductive, although the first layer of a Schottky arrangement according to the invention can of course also be p-conductive. If the first layer 14 is p-type, the second becomes Layer 16 is doped so that it is slightly p-conductive and the metal film 18 consists of a metal with low Normal potential, i.e. a base metal, less than about 4.3 eV, generally aluminum.

On a portion of the surface of the metal film 18 opposite the interface 20 is an electrode

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arranged. Typically, the electrode 22 is in the form of a grid, although other known shapes, for example a finger or a comb; the electrode is made of a metal with good electrical conductivity.

In the present exemplary embodiment of the invention, the electrode 22 has two sets of grid lines which run substantially parallel to each other and intersect the grid lines of the other arrangement. The electrode 22 occupies only a small area of the surface of the metal film 18, for example about 5-10% of the Surface of the film 18, since the solar radiation impinging on the electrode 22 reflects away from the arrangement 10 shall be. The task of the electrode 22 is to evenly absorb the material from the metal film 18 Current. The electrode 22 makes it easier to keep the series resistance of the arrangement 20 low, when operating as part of the circuit. However, it can be assumed that only one single grid share for an even power consumption is necessary in the case of an arrangement with small surface areas, which in some known form, such as fingers, or comb, can be designed.

An anti-reflective layer 24 is on the electrode 22 and the opposite surface of the interface 20 of the Metal film 18 not bent from the electrode 22 is attached. The anti-reflective layer 24 has an incidence surface 26 on which the solar radiation 28 can impinge. As is well known, one obtains an increase in solar radiation 28 which passes through metal film 18 and enters assembly 10, by adjusting the thickness of the anti-reflective layer 24

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of the order of magnitude of 7 \, / n , where TU is the wavelength of the radiation impinging on the incident surface 26, and η is the refractive index of the antireflection layer 24. The refractive index η of the antireflection layer 24 should have a suitable value so that the amount of solar radiation 28 incident on the metal film 18 is increased. If, for example, the metal film 18 consists of platinum with a thickness of 100 Å, a suitable antireflection _{layer 24 could consist of zirconium oxide ZrO 2} with a thickness of 500 Å with η = 2.1. As a result, the anti-reflective layer 24 reduces the amount of light that is reflected from the assembly 10. Normally, the anti-reflective layer 24 will consist of a dielectric material such as zinc sulfide, zirconium oxide or silicon nitride, but it can also be a transparent semiconducting material such as tin oxide doped with antimony or indium oxide doped with tin.

It is known that a boundary layer junction, commonly known as a Schottky barrier layer or barrier layer, is as a result of the contact of certain metals with certain semiconductor materials. With the Schottky arrangement 10 according to the present invention, the transition is made by contacting the metal film 18 with the second Layer 16 is formed at the interface 20. A Schottky barrier creates a space charge or a electric field in the semiconductor material dei / arrangement 10 from the interface 20 which penetrates into the second layer 16; this area is called impoverishment or Denotes restricted area. As a result of the decreasing doping concentration in the first layer 14 an electric field is also generated in this. As a result of the Schottky barrier layer at the interface 20 and the graded, decreasing doping concentration

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'Feeder first layer 14 extends an electrical Field essentially through the first and second layers 14 and 16, respectively. It is used at least for photo-voltage arrangements according to the present invention preferred that the electric field through both the first and extends through the second layer 14 and 16, respectively. With an electric field that runs through the first and the second Layer 14 or 16 extends, charge carriers that somewhere within these layers as a result of the absorption of solar radiation 28 by the electric field withdrawn either to the substrate 12 or to the metal layer 18. The substrate 12 is one of the electrodes the arrangement 10. If the electric field does not extend into a portion of the first or the second layer

14 or 16 of the arrangement 10 extends into it, are any Charge carriers that are generated in this quasi-neutral section, not with the help of a field withdrawn to an electrode and rely on diffusion to the depletion area in order to collect them can. In addition, some quasi-neutral area contributes to the current draw from the arrangement Series or series resistance at, which reduces the efficiency of the arrangement.

While the decreasing doping concentration within the first layer 14 is advantageous for a broadening of the electric field area of the arrangement 10, an ohmic contact between the first Layer 14 and substrate 12 are more easily formed because of the doping concentration at the first interface

15 has its maximum, and is, for example, of the order of 5 atom-96. The formation of an ohmic Contact at the point of contact 15 is advantageous in order to achieve a low series resistance for the semiconductor

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η 3

arrangement 10 to reach. Even if there is a uniform doping concentration through the first layer 14 prevails, an ohmic contact can be formed at the contact point 15, as long as the uniform Doping concentration is on the order of 5 atom-96.

The amorphous silicon of the first layer 14, which is through Glow discharge was produced in silane plus doping gas, and the amorphous silicon of the second layer 16, made by glow discharge in silane has properties that are useful for photovoltaic assemblies are ideally suited. The electron lifespan in amorphous silicon produced by glow discharge in silane

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is estimated to be around 10 see while the electron lifespan of amorphous silicon, which was obtained by sputtering or vapor deposition,

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is in the order of 10 see »

Measurements of the spectral sensitivity of the arrangement according to the invention show a high collection efficiency in the visible range of the spectrum, for example an average collection efficiency in the spectral range from 4000 & to 7000 Ä in the order of 50%.

The light absorption in the visible range, i.e. from 4000 Å to 7000 Å, is generated by glow discharge amorphous silicon is higher than that of monocrystalline silicon. In Figure 2 it is shown that amorphous Silicon has a larger absorption coefficient over the visible range than monocrystalline silicon. this means that a major part of amorphous silicon obtained by glow discharge can be thinner by a factor of 10 can as monocrystalline silicon to a comparable

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To achieve light absorption in the visible range.

Furthermore, there is the average density of states of amorphous silicon obtained by glow discharge on the order of 10 / cm or less. The average density of states by glow discharge Amorphous silicon produced decreases with increasing deposition temperature and increasing purity of the silane during production and is much lower than that of amorphous silicon produced in other ways, for example by atomization or vapor deposition, of which

19/3 average density of states is 10 vcm · ^ or more. It is noticeable that the density of states is inversely proportional to the square of the width of the depletion region. Since the density of states in amorphous silicon obtained by glow discharge is relatively low, a depletion width on the order of Λ * / m can be obtained. Evident for the average density of states near the center of the energy band is the fact that the life of the energy carrier * is inversely proportional to the average stand-tight _u Z. This fact in turn confirms that the carrier life of glow discharge amorphous silicon is longer than that of amorphous silicon produced by the aforementioned other methods.

FIG. 3 shows a device suitable for a glow discharge for producing the semiconductor arrangement 10 is designated as a whole by 30 according to the present invention. The glow discharge device 30 includes a chamber 32, which is through a bell jar 34, usually made of glass. In the vacuum chamber 32, an electrode 36 and a heating plate 38 are in

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at a distance therefrom and opposite the electrode 36. The electrode 36 is made of metal with good electrical conductivity, such as platinum, and is in the form of a screen or a coil. The heating plate 38 is made from a ceramic frame with enclosed heating coils, which are from a power source 40 outside the vacuum chamber 32 can be fed.

A first outlet 44 in the vacuum chamber 32 is connected to a diffusion pump, and a second outlet 46 is connected to a mechanical pump, and a third outlet 48 is connected to a gas supply known as QiAIe represents the various gases used during the glow discharge process. Although the second outlet 46 is described as being connected to a diffusion pump, it is assumed that a diffusion pump under Under certain circumstances is not necessary, since the mechanical pump connected to the first outlet 44, the system up to can evacuate at a sufficient pressure.

In manufacturing the semiconductor device 10, the substrate 12, such as 304 stainless steel, is made the heating plate 38 and connected to a socket of the voltage source 42, while the electrode 36 is connected to the opposite socket of the voltage source 42. Hence there is a voltage potential between electrode 36 and substrate 12. The voltage of the Voltage source 42 can either be DC voltage or it can be in the low frequency range of, for example 60 Hertz, or in the radio frequency range, for example in the high frequency range in the order of magnitude from MHz. When the voltage source 42 is supplying direct current, the electrode 36 is usually positive

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The socket of the voltage source 42 is connected, and the substrate 12 is connected to the negative socket of the voltage source 42 tied together. Therefore, the electrode 36 acts as the anode and the substrate 12 as the cathode when the voltage source 42 is switched on. This is called cathode direct current operation. However, in DC operation substrate 12 and electrode 36 also have reversed polarity, i.e. substrate 12 is the anode and the Electrode 36 is the cathode in what is referred to as DC anode operation. It was found that the Deposition speed slightly higher in cathode operation than is the case with anode operation. In addition, a high-frequency glow discharge operation be carried out in electrode-less glow discharge devices of known design, for example in capacitive high-frequency glow discharge systems and inductive high-frequency glow discharge systems.

However, a more even deposition can be achieved

ρ a large area, for example greater than 10 cm a glow discharge with direct current or lower alternating current than with electrode-less high frequency. Next the vacuum chamber 32 is usually also to a pressure evacuated from about 10 to 10 ~ Torr, and the substrate 12 is heated to a temperature in the range from 150 ° to 450 ° C, wherein the heating coils of the heating plates 38 are supplied with power.

Then an atmosphere of about 98.5% silane, SiH ,, and about 1.5% n-doping gas is introduced into the vacuum chamber so that a pressure of 0.1 to 5 Torr is created, and as a result the substrate increases. temperature to a value in the range from 200 ⁰ C to 500 ° C. Common n-type doping gases that can be used in glow discharge processes are phosphine, PH ,, and arsine AsH ,. It can also-

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if materials like antimony Sb, bismuth Bi, sodium hydride NaH and cesium nitride, CsN, can be used by placing them in an evaporator boat and leaving them in the atmosphere the vacuum chamber 32 is heated until the desired amount of doping gas or vapor is in the silane atmosphere is delivered.

Around the glow discharge between electrode 36 and substrate 12 initiate, the voltage source 42 is switched on, whereby the deposition of the doped, amorphous silicon layer 14 starts. Assume direct current cathode operation. For the deposition of the first layer 14 should the current density is on the order of 0.1 to 3.0 mA / cm at the surface of the substrate 12. The deposition rate of the amorphous silicon grows with the vapor pressure of the silane and the current density. At a pressure

of 2 Torr and a current density of 1 mA / cm to the cathode substrate 12 at a temperature of 350 ° C finds this Deposition of about 200 Å of doped amorphous silicon takes place in a few seconds. To the doping concentration of the first layer 14 to be graded or to be removed is additional during the glow discharge deposition Silane introduced into the vacuum chamber 32.

Once the glow discharge for direct current cathode operation has been initiated, electrons are emitted from the substrate 12 and strike SiH with silane molecules. together, whereby both molecules are ionized and dissociated. The positive silicon ions and the positive silicon hydride ions, SiH ⁺ , are attracted to the substrate 12, which forms the cathode, with silicon, which contains some hydrogen, being deposited on the substrate 12. It is believed that the presence of hydrogen in amorphous silicon is beneficial for its electrical properties.

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The atmosphere of the vacuum chamber 32 is then pumped out by the mechanical pump 46.

-6 When the vacuum chamber 32 is at a pressure of about 10 torr, essentially pure silane is introduced into the vacuum chamber 32 so that a pressure in the range of 0.1 to 5 torr is established. The glow discharge is restarted for 1 to 5 minutes at a current density of 0.3 mA / cm to 3.0 mA / cm at the first layer 14 for the deposition of the second layer 16 of amorphous silicon. It has been found dai3 the second layer 16 of amorphous silicon, which is prepared in essentially pure silane by the glow discharge, light n-type conductivity is, when deposited on the first layer 14 at a temperature above 100 ⁰ C.

The temperature of the substrate 12 during the glow discharge process can influence the composition and structure of the material deposited thereon as a result of the effects of auto-doping, the formation of a eutectic and as a result of induced crystallization, ie this deposition on a single crystal silicon substrate at temperatures above about 500 ⁰ C results in a deposition of polycrystalline silicon, and a deposition on a gold substrate at temperatures above 186 ⁰ C results in an induced crystallization of the deposited silicon.

After the first and second layers 14 and 16 have been deposited, the base body 13 can be subjected to a heat treatment in which it is exposed to ^{a temperature in the range from 200 °} C. to 450 ^{° C. for five minutes to a few hours.} It should be mentioned that the heat treatment lasts for several hours only at the lower temperatures.

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Usually, the heat treatment can be carried out so that the base body 13 after completion of the Glow process in the glow discharge device 30 leaves, or place the wafer in an oven of generally known type. The heat treatment can either be in Take place in a vacuum or in a molding gas atmosphere, i. 90% by volume nitrogen and 10% by volume oxygen or in one An atmosphere of pure nitrogen or pure oxygen. This process stage eliminates lattice defects in the base body made of amorphous silicon and improves the efficiency of the arrangement.

Next, the base body 13 in. A known vapor deposition ungsanlage given and the metal film 18 is vapor-deposited on the second layer 16. In the same way, the electrode 22 and the anti-reflective layer 24 on the metal film 18 by known vapor deposition and masking techniques deposited. The whole process can be carried out in a single facility, both for glow discharge as well as for evaporation.

It has also been found that the collection efficiency of the assembly 10 increases when it has a metal film 18 comprises a material belonging to the group of chromium, iridium, rhodium, platinum or palladium, and during is subjected to a heat treatment during manufacture. Usually, the heat treatment can then take place after the anti-reflective layer 24 has been deposited, or both before the electrode 22 is deposited as well as after the deposition of the anti-reflective layer 24. In particular, for the heat treatment, the Bring semiconductor device 10 into a heat treatment chamber of known type and a temperature

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undergo between 15O ⁰ C and 250 ° C for about 5 to 30 minutes. The heat treatment chamber can be evacuated or under a molding gas atmosphere, for example 90% by volume nitrogen and 10% by volume hydrogen or under an atmosphere of pure nitrogen or pure hydrogen. It has been found that this heat treatment increases the efficiency, increasing the height of the Schottky barrier layer, an improvement in the collection efficiency and a reduction in the effective series resistance of the device. The manufacture of the semiconductor device 10 is accomplished by connecting wire electrodes (not shown) to the substrate 12 and electrode 22 for connection to external circuitry.

During operation of the semiconductor arrangement 10, the substrate 12 can return unabsorbed solar radiation back into the first and reflect second layers 14 and 16, respectively, whereby the possibility for beam absorption is improved.

In Fig. 4, a second glow discharge device for producing the semiconductor device 10 is shown, which with 130 is designated. The device 130 is similar to FIG Device 30 constructed, in particular the vacuum chamber 132, the vacuum bell 134, the electrode 136, the Heating plate 138, the power source 140, the voltage source 142, the first outlet 144, the second outlet 146 and the third outlet 148 of device 130 the same as the vacuum chamber 32, the bell jar 34, the electrode 36, the heating plate 38, the power source 40, the voltage source 42, the first outlet 44, the second outlet 46 as well the third outlet 48 in the device 30. Unlike the device 30, the device I30 has an electrode 149, which has the shape of an umbrella. The umbrella

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electrode 149 consists of electrically conductive material, for example made of a metal such as stainless steel and has openings which are smaller than the cathode dark space area the glow discharge. The shield electrode 149 is in one between the electrode 136 and the heating plate 138 Distance arranged above the substrate 12, which is in the order of magnitude of the cathode dark space region of the glow discharge lies. The operation of device 130 differs from that of device 30 in that the substrate 12 is not electrically connected to the voltage source 142, but instead the shielding electrode 142. Hence is the shield electrode 149 with a socket of the voltage source 142 and the electrode I36 with the opposite Socket connected. Assuming direct current cathode operation, the positive ions are in the glow discharge drawn towards the shield electrode 149 when the voltage source 142 is switched on. Most of the positive ions will be however, pass through the openings of the shield electrode 149.

The device 130 with the shield electrode 149 can then can be used when the substrate 12 is an insulator on which no electrical contact is possible. The device However, 130 can also be used in the manufacture of assemblies be used with amorphous silicon, in which the substrate 12 is not an insulator.

The device 130 can, like the device 30, in the direct current cathode or anode operation.

In Fig. 5 is a second embodiment of a semiconductor arrangement shown with Schottky barrier layer or barrier layer according to the present invention and denoted by 110. The semiconductor assembly 110 includes

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an electrically conductive substrate 112. An intermediate layer 111 adjoins a surface of the substrate 112, and to this a base body 113. The body 113 contains a first layer 114 on the intermediate layer 111 opposite the substrate 112, and a second layer 116 on the first layer 114 opposite substrate 112. A semi-transparent metal film 118 is on the second layer 116 applied to the substrate 112 and forms between the two a boundary layer transition. An electrode 122 is attached to a portion of the metal film 118, while the remaining part of the metal film is provided with an anti-reflective layer 124. That Substrate 112, the first layer 114, the second layer 116, metal film 118, electrode 122, and anti-reflective layer 124 of assembly 110 are the same such as the substrate 12, the first layer 14, the second layer 16, the metal film 18, the electrode 22 and the Anti-reflective layer 24 of the semiconductor arrangement 10. The only difference between semiconductor arrangement 10 and semiconductor device 110 is that the device 110 has an intermediate layer 111, which in the Arrangement 10 does not exist.

The intermediate layer 111 consists of a material that has an ohmic contact both to the substrate 112 and to the first layer 114 caused. The intermediate layer 111 usually consists of doped amorphous germanium or from a compound of doped amorphous germanium and silicon. With each of these materials is the Layer 111 usually η-conductive if the second layer 16 is slightly η-conductive. It was determined, that amorphous germanium is a good material for forming an ohmic contact between doped amorphous Silicon and metallic substrate 112 represents. Into the-

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in particular, when the substrate 112 is made of aluminum, the electrical conductivity is between the first and second Layer 114 or 116 of the arrangement 110 and of the substrate 112 better than the electrical conductivity between first and second layers 14 and 16 of the arrangement 10 and the substrate 12.

The operation of the device 110 is the same as that previously described for the semiconductor device 10. The manufacture of the semiconductor device 110 is similar to that of the device 10, except that the intermediate layer 111 is deposited on the substrate 112 by a glow discharge prior to the first layer 114 is produced by glow discharge. ., Using an apparatus according to FIG 3, the production takes place of the intermediate layer 111 as follows: Substrate 112 wirdauf the heating plate 138 placed, the substrate is heated to a temperature in the range from 150 ⁰ C to 45O ⁰ C and the chamber 132 to a pressure of about 0.5 to 1.0. 10 "Torr. Next, gases determined by the desired composition of the intermediate layer 111 are introduced into the chamber 132 to a pressure of 0.1 to 5.0 Torr. If the intermediate layer is to consist of doped germanium, The atmosphere contains about 60% germanium hydrogen GeH ,, 39.5% silane SiH, and about 0.5% doping gas, for example phosphine PH ,, which is n-type. The glow discharge is then initiated and for about two seconds to deposit an intermediate layer 111 of approximately 200 Å in thickness The atmosphere in the vacuum chamber 32 is then pumped off by the mechanical pump 46. The rest of the manufacture of the semiconductor device 110 is the same as that previously described for the semiconductor device 10.

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Although the semiconductor devices 10 and 110 according to the present Invention as solar cells have been described, semiconductor arrangements 10 and 110 can be the same As a high-frequency photodetector, for example as an arrangement that responds to radiant energy, be used. It has been found that these photodetectors, in which a first layer of doped Amorphous silicon is adjacent to a second layer of amorphous silicon, which is created by a glow discharge in silane have high sensitivity to high frequencies on the order of 10 MHz and above exhibit. The amount of radiation energy impinging on the arrangement when the semiconductor arrangements are used 10 and 110 as a photodetector are not as critical as when they are used as solar cells. For the function of the arrangements 10 and 110 as photodetectors are therefore easily possible, for example that Removing the anti-reflective layer and replacing the grid electrode with a contact bracket.

The use of glow discharge amorphous silicon in photovoltaic and photodetector assemblies according to the present invention allows thinner base bodies than when arranged with the same Basic structure, but with single crystal silicon. Arrangements containing amorphous silicon produced by glow discharge are suitable for solar radiation absorption similar to that of photo voltage and Photodetector arrangements that have been produced using single crystal silicon, comparable whose main body is 10 times thicker. Hence the particular advantage of the present invention when used as photo voltage or photo

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detector arrangement the cost reduction through the use of thinner active areas. In addition, the present invention can be used as a photo voltage Arrangement also achieve a cost reduction in the generation of electrical energy from solar radiation, because less energy is consumed in the manufacture of the assemblies according to the present invention, since the Production takes place at lower temperatures than the production of single-crystal arrangements; also can Solar cells with larger areas are manufactured using single crystal arrays compared to solar cells.

It has also been found that semiconductor devices 10 and 110 are suitable for rectifying current in the dark. For example, shows a Schottky assembly 10 with a substrate 12 made of stainless steel, with a uniform phosphorus-doped first layer 14, with a metal film 18 made of palladium from 1000 Å to 2000 Å thick for making electrical contact, and without the grid electrode 22 and the anti-reflective layer 24 has a rectification ratio of 10 ⁴ at + 0.4 volts. Although the assemblies 10 and 110 are described as solar cells, they can also function as current rectifiers, it being understood that their effectiveness as rectifiers can be further increased by making minor modifications, for example removing the anti-reflective layers.

The semiconductor device according to the present invention, the first layer of which is made of doped amorphous silicon and the second layer of which consists of amorphous silicon, can either be used as a solar cell, as a photodetector or as a Rectifier work.

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Claims (8)

7711365 RCA Corporation, 30 Rockefeller Plaza, New York, NeY. 10020 (V.St.A.) claims: 1. Semiconductor arrangement with Schottky boundary layer, consisting of a substrate with an electrically conductive surface, characterized by a base body (13) made of amorphous silicon, which is produced by glow discharge in silane SiH. on the substrate (12), as well as through a metal film (18) on the body (13) with the formation of an edge layer transition at the interface (20) between metal film (18) and body (13), wherein the body (13) is heat-treated and at least a portion of the body (13) adjoining the substrate (12) is doped is to form a good ohmic contact with the substrate (12). 2. Arrangement according to claim 1, characterized in that the metal film (18) is at least semi-permeable to solar radiation is. 3. Arrangement according to claim 1 or 2, characterized in that the body (13) consists of a first layer (14) of doped amorphous silicon on the substrate (12) and of a second layer (16) over it the first layer (14) consists of essentially undoped amorphous silicon " ORIGINAL INSPECTEO 4. Arrangement according to claim 3, characterized in that the first layer (14) is n-conductive is. 5. Arrangement according to claim 3 or 4, characterized in that the doping concentration is selected within the first layer (14) such that its maximum at the first interface (15) between the first Layer (14) and substrate (12) and that it lies in the direction of the interface between the first layer (14) and the second Layer (16) decreases. 6. Arrangement according to one or more of claims 1 to 5, characterized in that the substrate (12) consists of aluminum. 7. The method for producing a semiconductor arrangement according to one or more of claims 1 to 6, characterized by the following steps: Application of a thin base body (13) made of amorphous silicon on a substrate (12) with an electrically conductive surface by glow discharge in silane, after which the body (13) ^ ei a temperature between 200 C and 450 ° C for a period of a few minutes to a few Hours treated wire ¹ ; Depositing a metal film (18) on the surface of the body (13), wherein - At least the first region of the body (13) bearing against the substrate (12) using one with silane mixed doping gas is produced. 709839/0862 8. A method for producing the base body according to claim 7, characterized in that on the Substrate (12) a first layer (14) made of doped amorphous Silicon is applied by glow discharge in a mixture of silane and a doping gas, and that by glow discharge a second layer (16) of amorphous silicon is produced in silane on the first layer (14).