RU2368038C1 - Method for manufacturing of multilayer photoconverter chips - Google Patents

Abstract

FIELD: physics, conductors.

SUBSTANCE: invention is related to solar engineering. Method consists in application of ohm contacts on back and frontal surfaces of multilayer semiconductor structure GaInP/Ga(In)As/Ge, grown on germanium substrate, separation of structure on chips by method of chemical etching, immunisation of side surface of chips by dielectric, removal of part of frontal contact layer of structure and application of anti-reflecting coat on frontal surface of structure. After application of ohm contact base onto back surface of structure, structure frontal surface is cleaned by method of ion-beam etching to the depth of 0.005-0.1 mcm. Base of ohm contacts are burnt in at the temperature of 360-370°C for 10-60 s. Base of ohm contacts is thickened by serial electrochemical deposition of gold, nickel and again gold layers through mask of photoresist, with total thickness of 1.6-3.5 mcm. Separating chemical etching of structure is carried out from the side of frontal surface to the depth of 15-50 mcm through mask of photoresist. Immunisation is carried out by application of silicon nitride. Chemical etching of structure contact layer is carried out in the areas that are free from ohm contact, afterwards anti-reflecting coating is applied in areas free of ohm contacts via slots in mask.

EFFECT: production of multilayer photoconverters with improved parametres.

4 cl, 11 dwg, 10 ex

Description

The invention relates to solar energy, in particular to a method for manufacturing chips of multilayer photoconverters, and can be used in the electronics industry to convert light energy into electrical energy.

A known method of manufacturing multilayer photoconverters (see "Features of the technology for producing solar cells based on AlGaPAs / GaAs heterostructures using the GLC method", Blagin A.V., Blagina L.V., Alfimova D.L., Sysoev I.A., Slutskaya OV Proceedings of the Ninth International Scientific and Technical Conference "Actual Problems of Solid-State Electronics and Microelectronics", Divnomorskoye, Russia, 2004) based on AlGaPAs / GaAs heterostructures using gradient liquid-phase crystallization. As contact materials for the p-type layer, chromium-copper and nickel-copper alloys were used, the resistance of which does not exceed 0.23 Ohm / cm ² , for the n-type layer a combination of two metals - vanadium and aluminum, whose resistance is 0.105 Ohm / cm ² . The efficiency of the photoconverter based on the Al0.33Ga0.67P0.05As0.95 / GaAs heterostructure, measured on a solar radiation simulator, was 21.5%.

The disadvantage of this method of manufacturing multilayer photoconverters is the high resistance of the ohmic contact, the complexity of manufacturing a semiconductor structure and low efficiency of the photoconverter.

A known method of manufacturing a photodetector element (see application RU No. 94021123, IPC H01L31 / 18, published on 04/20/1996) based on multilayer GaAs / AlGaAs heterostructures. The method consists in applying a sequence of layers on a semi-insulating gallium arsenide substrate: a conductive n ⁺ GaAs layer, a multilayer periodic structure of GaAs / AlGaAs and a second conductive n ⁺ GaAs layer, followed by etching of the upper conductive n ⁺ GaAs layer and a multilayer heterostructure in an aqueous solution hydrogen peroxide containing organic acid. The method allows to increase the accuracy and precision of etching in the manufacture of photodetector elements, to increase the yield of products and reduce the cost of photodetector elements.

The disadvantage of this method of manufacturing a photodetector element is the use of a gallium arsenide substrate instead of a germanium substrate, which leads to a deterioration of the parameters of the photoconverter.

A known method of manufacturing a solar cell (see application RU No. 93046763 IPC H01L 31/18, published September 20, 1995), consisting in the fact that at least one surface of the semiconductor substrate forms a structure of parallel grooves by mechanical removal or etching of the semiconductor material, separated by elevations tapering to the tops. A passivating layer is applied to the entire structured surface, after which the tops of the hills are cut to the depth of the passivating layer, resulting in the formation of parallel plateau-shaped areas from which the brackets extend. On plateau-like regions, as well as on one of the bevels of each region, material is formed that forms electrically conductive contacts. The solar cell contains a semiconductor substrate, on one surface of which a structure of hills with plateau-like peaks and with side bevels is formed. Electrically conductive contacts are located on plateau-like peaks and partially on bevels. The surface of the semiconductor substrate in the region between the contacts is coated with a passivating material.

The disadvantage of this method of manufacturing a solar cell is the complexity of the process, the possible occurrence of structural defects in the process of cutting the tops of the hills, which leads to a deterioration of the parameters of the photoconverter.

The closest to the claimed technical solution according to the set of essential features is a method of manufacturing multilayer photoconverter chips (see "Research and development of GalnP / GaAs / Ge multijunction solar cells", An Xinxin, Garnelly Dario Albino, Denisov Alexey, Di Lillo Luigi, Sacchetto Davide , Fisichella Salvatore, Reddy Pallavi, Zneng Liqiancg, Institut National Polytechnigue de Grenoble, Nanotech Labs Project, Grenoble, 2007) based on the AlGaPAs / GaAs / Ge heterostructure. In this method, the structure is grown on a germanium substrate, ohmic contacts are deposited by sequential deposition of layers of titanium and silver, the ohmic resistance of which is 10 ^-6 Ohm / cm ² , an antireflection coating is applied by successive deposition of ZnS and MgF ₂ layers.

The disadvantage of this method of manufacturing chips of multilayer photoconverters is the small thickness of the ohmic contacts, which impedes the subsequent operation of soldering solar cells, and the presence of leakage of the pn junction, which leads to a deterioration of the parameters of the photoconverters.

The objective of the proposed technical solution is to improve the parameters. This object is achieved in that a method for manufacturing multilayer photoconverter chips based on a multilayer GalnP / Ga (ln) As / Ge semiconductor structure grown on a germanium substrate involves applying ohmic contacts to the back and front surfaces of the structure, dividing the structure into chips by chemical etching, passivation of the chip’s side surface by a dielectric, removal of a part of the front contact layer of the structure by chemical etching and the application of an antireflection coating on the front th surface structure. In contrast to the prototype method, after applying the ohmic contact base to the back surface of the structure, the front surface of the structure is cleaned by ion beam etching to a depth of 0.005-0.1 μm, then the ohmic contact base is sprayed onto the front surface of the structure through a photoresist mask. After spraying, the bases of ohmic contacts are incinerated at a temperature of 360-370 ° C for 10-60 s. At the next stage, the base of ohmic contacts is thickened by electrochemical deposition of successive layers of gold, nickel and again gold with a total thickness of 1.6-3.5 μm through a photoresist mask. Separate chemical etching of the structure is carried out from the front surface to a depth of 15-50 μm through a photoresist mask. Passivation is carried out by applying a layer of silicon nitride. Then carry out chemical etching of the contact layer of the structure in places free of ohmic contact, after which an antireflection coating is applied in places free of ohmic contacts through windows in the mask.

The multilayer semiconductor structure of GalnP / Ga (ln) As / Ge can be grown on a p-type germanium substrate. In this case, on the back surface of the structure, an ohmic contact base of 0.4-0.5 μm thick is sprayed, consisting of a successively arranged alloy layer containing 95 wt.% Silver and 5 wt.% Manganese, nickel and gold layers, and on the frontal surface structures spray the base of the ohmic contact with a thickness of 0.2-0.4 μm, consisting of a successively arranged layer of an alloy containing 90 wt.% gold and 10 wt.% germanium, nickel and gold layers.

Electrochemical deposition of gold can be carried out at a temperature of 60-75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] 20-40 C ₆ H ₈ O ₇ 50-100 Water rest

at pH 5.5-5.0.

An antireflective coating can be applied by successive sputtering of ZnS layers with a thickness of 0.045 μm and a thickness of 0.095 μm MgF ₂ in places free from ohmic contacts through windows in a mask made of magnetic material and fixed to the front surface of the structure using a magnet located on the back side of the structure.

The front surface is cleaned by ion beam etching to a depth of 0.005-0.1 μm to improve contact adhesion to the semiconductor structure and to reduce ohmic resistance. When etching to a depth of less than 0.005 μm, it is impossible to remove surface contaminants, when etching to a depth of more than 0.1 μm, structural defects arise due to its bombardment by ions during etching.

The burning of ohmic contacts is carried out to reduce their ohmic resistance. When the ignition temperature is less than 360 ° C or when the ignition time is less than 10 s, the ohmic resistance increases. At an ignition temperature greater than 370 ° C or an ignition time greater than 60 s, the gold-germanium alloy diffuses into the semiconductor and the pn junction is shorted.

With the electrochemical deposition of layers of gold, nickel and again gold with a total thickness of less than 1.6 microns, it is impossible to solder the solar cells. With a thickness of more than 3.5 μm, stressed layers arise, as a result of which the adhesion of the ohmic contact to the semiconductor structure decreases and its peeling, the ohmic contact grows in width and the photosensitive surface of the semiconductor structure grows.

The depth of the chemical separation etching from the front surface of the structure is due to the fact that when the etching depth is less than 15 μm, it is not possible to separate the structure into separate solar cells. With an etching depth of more than 50 μm, further work with the semiconductor structure is impossible due to its fragility.

The use of silicon nitride for passivation of the side surface of the chips is due to its high barrier properties for the diffusion of water and oxygen molecules, as well as its low oxidation rate. Also, silicon nitride is characterized by high chemical resistance to many chemical reagents.

The sequential sputtering of the ohmic contact base layers from the back of the structure is due to the fact that the alloy containing silver 95 wt.% And manganese 5 wt.%, Has good adhesion to the surface of the structure and low ohmic resistance of the order of 10 ^-6 Ohm / cm ² . A layer of nickel is applied due to its refractoriness, which is necessary for the subsequent burning operation — nickel does not allow gold to completely diffuse into the semiconductor. The last layer of gold is applied for the subsequent operation of electrochemical buildup of the ohmic contact base. The total thickness of the base of the contact is 0.4-0.5 microns. When the thickness of the basis of the ohmic contact is less than 0.4 μm, the contact is completely ignited during the subsequent burning operation. Creating the basis of an ohmic contact with a thickness of more than 0.5 μm is irrational due to the large consumption of gold in the process of deposition.

The sequential deposition of the ohmic contact base layers from the front of the structure surface is due to the fact that the alloy containing 90 wt.% Gold and 10 wt.% Germanium has good adhesion to the structure surface and low ohmic resistance of the order of 10 ^-6 Ohm / cm ² . A layer of nickel is applied due to its refractoriness, which is necessary for the subsequent burning operation — nickel does not allow gold to completely diffuse into the semiconductor. The last layer of gold is applied for the subsequent operation of the electrochemical build-up of ohmic contact to ensure the best adhesion. The total thickness of the base of the contact is 0.2-0.4 microns. When the thickness of the basis of the ohmic contact is less than 0.2 μm, the contact is completely ignited during the subsequent burning operation. The creation of the basis of ohmic contact on the front surface is carried out using a photoresist mask by the method of explosive photolithography, the technical capabilities of which prevent the deposition of the basis of the ohmic contact with a thickness of more than 0.4 μm.

The temperature of the process of electrochemical deposition of gold layers is due to the fact that at a temperature of less than 60 ° C the deposition rate of gold is very low, at a temperature of more than 75 ° C the deposition rate is too high, and both parameters lead to a deterioration in the quality of the deposited layer. When keeping

K [Au (CN) ₂ ] is less than 20 g / l or more than 40 g / l, when the content of C ₆ H ₈ O _{7 is} less than 50 g / l or more than 100 g / l in the electrolyte and worsens at pH less than 5.0 or more 5.5 the quality of the deposited layer of gold and decreases the adhesion of the deposited contact to the previously deposited ohmic contact base. Also, the ohmic contact spreads in width, which increases the area of shading of the photosensitive surface of the structure.

The choice of materials for creating an antireflection coating and the thickness of the ZnS and MgF ₂ layers are due to the fact that in the wavelength range of 0.4-0.9 μm, the reflection coefficient of this antireflection coating does not exceed 1-2%, and therefore, when it is applied, a significant increasing the quantum yield of the photoconverter. The use of a mask for applying an antireflection coating made of magnetic material and fixed to the front surface of the structure with a magnet located on the back side of the structure is due to the ease and high accuracy of combining the mask and plate when creating an antireflection coating.

The claimed technical solution is illustrated by drawings, where:

figure 1 shows a diagram of a multilayer semiconductor structure GalnP / Ga (ln) As / Ge;

figure 2 shows a deposition scheme of the back base of the ohmic contact Ag (Man) / Ni / Au and create a photoresist mask;

figure 3 shows a deposition scheme of the facial basis of the ohmic contact Au (Ge) / Ni / Au through a photoresist mask;

figure 4 shows a diagram of a photoresist mask;

figure 5 is a diagram of the galvanic deposition of an ohmic contact Au / Ni / Au through a photoresist mask;

figure 6 shows a scheme for creating a photoresist mask and a scheme for applying chemically resistant varnish;

7 shows a separation chemical etching scheme;

on Fig shows a diagram of chemical etching of the contact layer of the structure;

Fig.9 shows a deposition scheme of the antireflection coating Zones + Miff ₂ through windows in a magnetic mask;

figure 10 shows the arrangement of the chips of multilayer photoconverters on a semiconductor wafer (section - side view);

figure 11 shows the arrangement of the chips of multilayer photoconverters on a semiconductor wafer (top view).

Figures 1-11 show: 1 — GaAs contact layer, 2 — GalnP / Ga (ln) As structure, 3 — germanium substrate, 4 — back side of the substrate, 5 — back base of the ohmic contact, 6 — photoresist mask, 7 — face basis of ohmic contact, 8 — photoresist mask, 9 — thickened ohmic contact, 10 — photoresist mask, 11 — chemically resistant varnish, 12 — separation meshes, 13 — etched area of the contact layer, 14 — antireflection coating, 15 — photosensitive structure region, 16 - a mask made of magnetic material.

The inventive method of manufacturing chips of multilayer photoconverters is carried out on the basis of a multilayer semiconductor structure GalnP / Ga (ln) As / Ge (see figure 1), consisting of a contact layer of GaAs 1 and structure GalnP / Ga (ln) As 2 grown on a germanium substrate 3. The process of manufacturing a photoconverter is carried out in several stages: carry out chemical etching of the back side 4 of the substrate 3 to a depth of 20-30 μm in the etchant CP4, spraying the back base of the ohmic contact 5 of the above composition (see figure 2) with a thickness of 0.4- 0.5 μm vacuum method but thermal evaporation at the facility - a vacuum universal post VUP-5M. The front surface of the structure is cleaned by ion-beam etching at the Rokappa IBE ion-beam etching unit to a depth of 0.005-0.1 μm. A photoresist mask 6 is created on the front surface of the structure and a face base of the ohmic contact 7 of the above composition (see FIG. 3) 0.2–0.4 μm thick is sprayed onto it using a vacuum-thermal evaporation method at the installation - universal vacuum post VUP-5M . The base of ohmic contacts is incinerated at a temperature of 360-370 ° C for 10-60 s. A photoresist mask 8 (see Fig. 4) is created on the front surface of the structure, and a thickened ohmic contact 9 (see Fig. 5) is created by electrochemical deposition of successively layers of gold, nickel and again gold with a total thickness of 1.6-3.5 microns. The electrochemical deposition of gold layers is carried out at a temperature of 60-75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] 20-40; C ₆ H ₈ O ₇ 50-100; water rest

at pH 5.5-5.0.

A photoresist mask 10 is created on the front surface of the structure, the back side of the structure is covered with chemically resistant varnish 11 (see Fig. 6) and chemical separation etching of the semiconductor structure is performed (see Fig. 7), i.e. create separation mesas 12, to a depth of 15-50 microns in two stages: at the first stage, the semiconductor structure is etched to the germanium substrate in the etchant containing the components in the following ratio, parts by weight:

K ₂ Cr ₂ O ₇ 80-110; HBr 80-110 water rest,

at the second stage, the germanium substrate is etched in the etchant containing the components in the following ratio, parts by weight:

Ce (SO ₄ ) ₂ * 4H ₂ O 25-35; H ₂ SO ₄ 3.5-4.5; water rest.

Passivation of the side surface of the chips is carried out by applying a layer of silicon nitride by plasma-chemical deposition under reduced pressure using high-frequency plasma on a plasma-chemical deposition of dielectrics Rokappa PCVD. Plasma performs the following functions: plasma stimulation of the reaction reduces the deposition temperature of silicon nitride films (about 200 ° C), accelerates the dissociation of working gas molecules, generates radicals - the most active chemical particles, intensifies the diffusion of particles to the substrate and their migration over the surface of the substrate, promotes the re-evaporation of adsorbed particles, which increases the rate of formation of nuclei, islands, and, in general, silicon nitride films.

Local chemical etching of the contact layer of the structure is carried out (see Fig. 8) in places free from ohmic contact to open the photosensitive surface of the solar cell. The main objective of this stage is to develop conditions for the complete reproducible etching of the GaAs contact layer of the GalnP / Ga (ln) As / Ge semiconductor heterostructure. The etching is carried out sequentially in two stages: at the first stage, oxides are removed from the surface of the structure in the etchant containing the components in the following ratio, parts by weight:

NH ₄ OH 2-3; H ₂ O ₂ 6-7; water rest,

at the second stage, the contact layer of the structure is completely etched to the GalnP stop layer in the etchant containing the components in the following ratio, parts by weight:

lemon acid 550-570; H ₂ O ₂ 60-70; water rest.

The composition of the ammonia-peroxide etchant is selected to set the optimum etching rate: with an increase in the concentration of ammonia and hydrogen peroxide in the etchant, the etching rate of the contact layer of the structure sharply increases, which greatly complicates the process control. A citric acid based etchant gives a good surface and a small seed under the ohmic contact of the order of 0.25-0.35 microns, even with a strong grinding over time. Grinding is necessary for 100% etching of the contact layer of the structure. By varying the ratio of these etchant components and the etching time, solar cells were obtained with a minimum reflection coefficient and, accordingly, a maximum photocurrent density.

The antireflection coating 14 is sprayed (see Fig. 9) by vacuum thermal evaporation in a facility - universal vacuum unit VUP-5M by sequential spraying of ZnS layers 0.045 μm thick and 0.095 μm thick MgF ₂ in places free of ohmic contacts (i.e. to the photosensitive region of the structure 15, see figure 10, figure 11) through the windows in the mask 16 (see figure 9) made of magnetic material and fixed to the front surface of the structure with a magnet located on the back side of the structure.

Example 1

The chips of multilayer photoconverters based on the multilayer semiconductor structure GalnP / Ga (ln) As / Ge grown on a p-type germanium substrate were fabricated. The chip manufacturing process is carried out in several stages. Chemical etching of the back side of the structure to a depth of 20 μm was carried out, the backbase of an ohmic contact 0.5 μm thick was sprayed on the installation - universal vacuum unit VUP-5M by sequential spraying of layers of an alloy containing silver 95 wt.% And manganese 5 wt.%, Nickel and gold. The front surface of the structure was cleaned on a Rokappa IBE ion beam etching unit to a depth of 0.005 μm. A photoresist mask was created on the front surface of the structure, an ohmic contact base 0.2 μm thick was sprayed onto the front surface of the structure on the installation - universal vacuum unit VUP-5M by sequential spraying of layers of an alloy containing 90 wt.% Gold and 10 wt.% Germanium and gold. The base of ohmic contacts was incinerated at a temperature of 370 ° C for 10 s. A photoresist mask was created on the front surface of the structure, and ohmic contacts were thickened by electrochemical deposition of successively layers of gold, nickel, and again gold with a total thickness of 3.5 μm. The electrochemical deposition of gold layers was carried out at a temperature of 75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] 40; C ₆ H ₈ O ₇ one hundred; water rest

at pH 5.0.

A photoresist mask was created on the front surface of the structure, the back side of the structure was covered with chemically resistant varnish, chemical separation of the semiconductor structure was carried out to a depth of 15 μm in two stages: at the first stage, the semiconductor structure was etched to a germanium substrate in the etchant containing the components in the following ratio, mass parts:

K ₂ Cr ₂ O ₇ 110; HBr 110; water rest,

at the second stage, the germanium substrate was etched in the etchant containing the components in the following ratio, parts by weight:

Ce (SO ₄ ) ₂ * 4H ₂ O 35; H ₂ SO ₄ 4,5; water rest.

The side surface of the chips was passivated by applying a layer of silicon nitride at the Rokappa PCVD plasma-chemical deposition apparatus. Local chemical etching of the contact layer of the structure in places free of ohmic contact was carried out in two stages: at the first stage in the etchant containing the components in the following ratio, parts by weight:

NH ₄ OH 3; H ₂ O ₂ 7; water rest,

at the second stage in the etchant containing components in the following ratio, parts by weight:

lemon acid 570; H ₂ O ₂ 70; water rest.

An anti-reflective coating was sprayed on the installation — universal vacuum unit VUP-5M by sequential spraying of 0.045 μm thick ZnS layers and 0.095 μm thick MgF ₂ in places free of ohmic contacts through windows in a mask made of magnetic material and fixed to the front surface of the structure with a magnet located on the back of the structure.

Example 2

Chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.1 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.4 μm, and the ohmic contacts were burned at at a temperature of 360 ° C for 60 s, the thickness of the ohmic contact deposited by the electrochemical method was 1.6 μm. The electrochemical deposition of gold layers was carried out at a temperature of 60 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] twenty; C ₆ H ₈ O ₇ fifty; water rest.

at pH 5.5.

Separation chemical etching of the semiconductor structure was carried out to a depth of 50 μm.

Example 3

The chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.1 μm, the thickness of the ohmic contact sprayed onto the front surface of the structure was 0.2 μm, and the ohmic contacts were burned at at a temperature of 370 ° C for 60 s, the thickness of the ohmic contact deposited by the electrochemical method was 1.6 μm. The electrochemical deposition of gold layers was carried out at a temperature of 75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] twenty; C ₆ H ₈ O ₇ fifty; water rest

at pH 5.0.

Separation chemical etching of the semiconductor structure was carried out to a depth of 50 μm.

Example 4

The chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.1 μm, the thickness of the ohmic contact sprayed onto the front surface of the structure was 0.2 μm, and the ohmic contacts were burned at at a temperature of 360 ° C for 10 s, the thickness of the ohmic contact deposited by the electrochemical method was 3.5 μm. The electrochemical deposition of gold layers was carried out at a temperature of 60 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] twenty; C ₆ H ₈ O ₇ fifty; water rest

at pH 5.5.

Separation chemical etching of the semiconductor structure was carried out to a depth of 15 μm.

Example 5

The chips of multilayer photoconverters were manufactured by the method described in example 1 with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.005 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.4 μm, and the ohmic contacts were burned at a temperature of 370 ° C 10 s, the thickness of the ohmic contact deposited by the electrochemical method was 1.6 μm. The electrochemical deposition of gold layers was carried out at a temperature of 60 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] 40; C ₆ H ₈ O ₇ one hundred; water rest

at pH 5.0.

Separation chemical etching of the semiconductor structure was carried out to a depth of 15 μm.

Example 6

The chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.005 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.4 μm, and the ohmic contacts were burned at a temperature of 360 ° C 60 s, the thickness of the ohmic contact deposited by the electrochemical method was 3.5 μm. The electrochemical deposition of gold layers was carried out at a temperature of 75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] twenty; C ₆ H ₈ O ₇ fifty; water rest

at pH 5.5.

Separation chemical etching of the semiconductor structure was carried out to a depth of 50 μm.

Example 7

Chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.01 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.3 μm, and the ohmic contacts were burned at at a temperature of 365 ° C for 30 s, the thickness of the ohmic contact deposited by the electrochemical method was 2 μm. The electrochemical deposition of gold layers was carried out at a temperature of 70 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] thirty; C ₆ H ₈ O ₇ 70; water rest

at pH 5.0.

Separation chemical etching of the semiconductor structure was carried out to a depth of 30 μm.

Example 8

Chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.05 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.2 μm, and the ohmic contacts were burned at at a temperature of 370 ° C for 30 s, the thickness of the ohmic contact deposited by the electrochemical method was 2 μm. The electrochemical deposition of gold layers was carried out at a temperature of 60 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] 40; C ₆ H ₈ O ₇ 90; water rest

at pH 5.0.

Separation chemical etching of the semiconductor structure was carried out to a depth of 20 μm.

Example 9

The chips of multilayer photoconverters were manufactured by the method described in example 1 with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.008 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.3 μm, and the ohmic contacts were burned at a temperature of 370 ° C 10 s, the thickness of the ohmic contact deposited by the electrochemical method was 3.5 μm. The electrochemical deposition of gold layers was carried out at a temperature of 60 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] twenty; C ₆ H ₈ O ₇ fifty; water rest

at pH 5.5.

Separation chemical etching of the semiconductor structure was carried out to a depth of 30 μm.

Example 10

The chips of multilayer photoconverters were manufactured by the method described in example 1, with the following distinctive features: the front surface of the structure was cleaned to a depth of 0.005 μm, the thickness of the ohmic contact deposited on the front surface of the structure was 0.4 μm, and the ohmic contacts were burned at a temperature of 360 ° C 30 s, the thickness of the ohmic contact deposited by the electrochemical method was 2.5 μm. The electrochemical deposition of gold layers was carried out at a temperature of 75 ° C from an electrolyte containing components in the following ratio, parts by weight:

K [Au (CN) ₂ ] thirty; C ₆ H ₈ O ₇ 80; water rest

at pH 5.0.

Separation chemical etching of the semiconductor structure was carried out to a depth of 50 μm.

The result of the process of manufacturing chips of multilayer photoconverters was the improvement of the parameters of photoconverters, obtaining low ohmic contact resistance of the order of 10 ^-6 Ohm / cm ² , low reflection coefficient of the order of 1-2%, which leads to maximum efficiency of converting solar energy into electrical energy.

Claims (4)

1. A method of manufacturing chips of multilayer photoconverters based on a GaInP / Ga (In) As / Ge multilayer semiconductor structure grown on a germanium substrate, including applying ohmic contacts to the back and front surfaces of the structure, separating the structure into chips by chemical etching, passivation of the side surface of the chips dielectric, removing part of the front contact layer of the structure by chemical etching and applying an antireflection coating to the front surface of the structure, characterized The fact is that after applying the ohmic contact base to the back surface of the structure, the front surface of the structure is cleaned by ion beam etching to a depth of 0.005-0.1 μm, the ohmic contact base is sprayed onto the front surface of the structure through a photoresist mask, and the base of ohmic contacts is incinerated when at a temperature of 360-370 ° C for 10-60 s, thicken the base of ohmic contacts by electrochemical deposition of successive layers of gold, nickel and again gold through a photoresist mask, total th thickness of 1.6-3.5 μm, conduct chemical separation etching of the structure from the front surface to a depth of 15-50 μm through a photoresist mask, the aforementioned passivation is carried out by applying a layer of silicon nitride, then chemical etching of the contact layer of the structure in places free from ohmic contact, after which an antireflection coating is applied in places free from ohmic contacts through windows in the mask. 2. The method according to claim 1, characterized in that the multilayer semiconductor structure GaInP / Ga (In) As / Ge is grown on a p-type germanium substrate, and the sprayed bases of ohmic contacts are made on the back surface of the structure from a successively deposited layer of an alloy containing silver 95 wt.% And manganese 5 wt.%, Layers of nickel and gold, and on the front surface of the structure from successively arranged alloy layer containing 90 wt.% Gold and 10 wt.% Germanium, nickel and gold layers, with a total thickness of 0.2 -0.4 microns. 3. The method according to claim 1, characterized in that the electrochemical deposition of gold layers is carried out at a temperature of 60-75 ° C from an electrolyte containing components in the following ratio, parts by weight:
K [Au (CN) ₂ ] 20-40 C ₆ H ₈ O ₇ 50-100 water rest,
at pH 5.5-5.0. 4. The method according to claim 1, characterized in that the antireflection coating is applied by sequential sputtering of ZnS layers with a thickness of 0.045 microns and MgF ₂ with a thickness of 0.095 microns in places free from ohmic contacts through windows in a mask made of magnetic material and fixed to the front surface of the structure with using a magnet located on the back of the structure.

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