JPH0550870B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Application of the Invention" The present invention relates to a photoelectric conversion element ( The present invention relates to a method for manufacturing a photoelectric conversion device capable of generating a high voltage by electrically connecting a plurality of elements (simply referred to as elements) in series.

"Prior Art" Conventionally, amorphous semiconductors are known as non-single crystal semiconductors to which hydrogen or halogen elements are added. However, since such semiconductors have an amorphous structure and do not actively use crystallinity,
The carrier depletion layer of the I-type semiconductor layer in the PIN junction is as narrow as 0.3 μ or more, and the AM1 (100 mW/cm ² )
Deterioration occurred due to light irradiation.

"Problems to be Solved by the Present Invention" The present invention promotes crystallization in the active semiconductor region of a non-single crystal semiconductor including such an amorphous semiconductor, prevents deterioration due to light irradiation, and
A photoelectric conversion device having a PIN junction is characterized in that the depletion layer to the I-type semiconductor is made large and wide, with a width of 1 μ or more.

Furthermore, the non-active semiconductor region constituting the connecting portion is made of amorphous semiconductor with high resistance to prevent leakage between electrodes in this non-active region.

"Means to Solve the Problem" The present invention transmits a pulse of strong light (pulse width 10 to 100 ns) with a wavelength of 500 nm or more from the transparent electrode side to the non-single crystal semiconductor inside the electrode. ) to irradiate the I-type semiconductor layer and P close to it.
Alternatively, crystallinity can be promoted while holding hydrogen or a halogen element inside the N-type semiconductor layer.

In particular, the present invention has a low light absorption of 500 nm or more, generally 0.5 to 2μ, for example 0.53μ or 1.06μ.
So-called optical annealing was performed by irradiating strong pulsed light from a YAG laser to promote the crystallinity of the I-type semiconductor as a whole or to a sufficiently deep region inside.
For this reason, a wavelength of 500 nm or more was used for light, where the light absorption coefficient of semiconductors is relatively small.

In the present invention, the accompanying increase in electrical conductivity caused by this optical annealing must not impede isolation in an integrated structure. Therefore, in the method of the present invention, this photoannealing was performed only on the active semiconductor region. Furthermore, at the same time as or after this optical annealing, a laser beam (Q switch) is applied to the non-single crystal semiconductor in order to form a connection part in this conductive film and the inactive region below it.
It was scribed and removed using a YAG laser beam.

"Effect" As a result, the crystallization promoting region obtained by laser annealing does not do anything to the isolation region between each cell, so manufacturing of the integrated photoelectric conversion device is completed without any other extra steps. It has the advantage of being able to

The arrangement, size, and shape of the elements in the device of the present invention are determined by design specifications. However, in order to simplify the content of the present invention, the following details will be explained with reference to the first electrode on the lower side (substrate side) of the first element and the second electrode of the second element disposed on the right side thereof. The pattern is based on the case where the electrodes (on the semiconductor, that is, on the side away from the substrate) are electrically connected in series.

Then, the laser beam for LS is placed at this specified position.
For example, a YAG laser (focal length 40 nm) with a wavelength of 1.06μ (light diameter approximately 50μ) or 0.53μ (light diameter approximately 25μ) is irradiated.

Further, it is moved at an operating speed of 0.05 to 5 m/min, for example, 30 cm/min, to create an open groove in a dependent relationship with the previous process.

In the present invention, when the substrate is made of translucent glass,
In addition, a semiconductor is formed on a non-transparent substrate, and the upper surface is annealed with a laser beam of 500 nm or more (the energy density is 1 × 10 ⁴ to 1 × 10 ⁶ W/cm ² , and the laser scribe is 5× of the actual energy density
10 ⁶ - 5 × 10 ⁷ W/cm ² ), which increases the yield from about 60% to 87 ^% without increasing the manufacturing process. An object of the present invention is to provide a method for manufacturing an epoch-making photoelectric conversion device.

The details of the invention are shown below with reference to the drawings.

Example 1 FIG. 1 is a longitudinal sectional view showing the manufacturing process of the present invention.

In the drawing, a substrate having an insulating surface, such as a glass substrate 1, is shown with a length (in the left-right direction in the drawing).
A size of 10 cm and a width of 10 cm was used. Further, on this upper surface, a first conductive film 2 and a transparent conductive film 2 are applied over the entire surface.
It was formed to a thickness of 0.1 to 0.5μ.

This transparent conductive film 2 is a transparent conductive film whose main component is tin oxide to which a halogen element such as fluorine is added, or ITO (indium tin oxide) (500
~5000 Å (typically 500 to 1500 Å) was formed by sputtering or spraying to form the first conductive film.

After that, an average output of 0.3 to 3 W (focal length 40 mm) is applied from the top of this substrate using a YAG laser (wavelength 0.53 μ (pulse width 30 ns) processing machine (manufactured by NEC Corporation)), and a laser beam with a diameter of 5 mmφ is focused. The spot diameter is 20 to 70μφ, typically 40μφ, and is controlled by a microcomputer to irradiate the laser beam from above, and by scanning, the first spot for the scribe line is
to form an open groove 13 in each active element region 31,1.
1, a first electrode 15 was produced by laser scribing (referred to as LS).

The open groove 13 formed by LS is approximately 50μ in width and length.
The length was 10 cm, and the depth was completely cut and separated to form the first electrode.

Thus, the first element 31 and the second element 11
The width of the area constituting the area is 5 to 40 mm, for example 10 mm.

After this, plasma CVD method is applied to this top surface.
A non-single-crystal semiconductor layer 3 doped with an octa-element or a halogen element that has a PIN junction, that is, a non-single-crystal semiconductor that generates photovoltaic force when irradiated with light, is heated by CVD or LPCVD to reduce the average oxygen concentration in the I-type semiconductor. 5×10 ¹⁸ cm ^-3 or less, and the thickness is 0.3 to 3.0μ
Typically, it was formed to a thickness of 1.5μ.

A typical example is when light irradiation is from the plate-raising side, so P-type (SixC _1-X 0<X<1) semiconductor (approximately
200 Å) - I-type amorphous or cell-amorphous silicon semiconductor (approximately 1.5 μ) - N-type microcrystalline (approximately 500 Å) non-single crystal semiconductor 3 having one PIN junction is uniformly distributed over the entire surface. It was formed with a film thickness of .

Furthermore, as shown in FIG.
The open groove 14 was formed by the second LS process.

In this drawing, the first and second open grooves 13, 14
The centers of the two are shifted by 100μ.

The second open groove 18 thus exposed the side surfaces 8, 9 of the first electrode.

Furthermore, in the present invention, only the surface of the transparent conductive film 15 of the first electrode 2 may be exposed;
0.8W was a little too strong, and the entire depth of this first electrode 15 was removed. However, that aspect 8
(side side only or side and top edge) Fig. 1C
Even if the connector 30 and the second electrode 38 are brought into close contact with each other, the contact resistance is generally an oxide-oxide contact (tin oxide-ITO contact), and no insulating barrier is formed at this interface, so there is no practical problem. I stopped talking.

In FIG. 1, a second surface conductive film 5 and a connector 30 were further formed on this upper surface as shown in FIG. 1C.

Furthermore, in the method of the present invention, YAG that emits light with a wavelength of 500 nm or more (generally 500 nm or 1.06μ)
An overview of the pulsed light laser annealing device and its method will be shown.

The irradiated structure is shown in FIG. 1B or C.

The structure before or after forming the second transparent electrode 5 was used as a target substrate in the optical annealing process.

The irradiation light area of the light source was YAG pulsed laser light with a size of 1 mm x 9 mm. In particular, this width is the width of the active region ±
⁰ ₁ mm, and the entire active region was photoannealed in one scan. For this reason, it is set to 9 mm here.
Also, in relation to the scan speed, the thickness should be reduced by 1
To control the irradiation energy density as mm,
It may be varied from 100μ to 3mm.

Here, a NEC laser oscillator was used.

Furthermore, this laser light is focused into a rectangular shape by a lens and has a pulsed light (frequency 300Hz to 30KHz).
5kw/cm ² (for width 1mm).

This irradiation light 25 was irradiated onto the irradiated surface of a moving base at a constant speed.

In this way, in a non-single crystal semiconductor, crystallization can be promoted in a region with a depth of 3000 to 5000 Å, which is the full thickness of the I layer (in the case of a wavelength of 1.06 μ) or about half of that when using a wavelength of 0.53 μ. was completed. The fact of this crystallization was found by performing laser Raman spectroscopy after this step. In addition, since the annealing of the method of the present invention is a light pulse annealing, there is little degassing of hydrogen or halogen elements already contained to the outside during crystallization, and dangling bonds at grain boundaries are removed. Can be neutralized. In addition, since crystallinity or orderliness is promoted by photoannealing, the photodegradation characteristics are reduced, and in addition, the width of the depletion layer in the I layer in the amorphous semiconductor between PN and PN is made more crystalline than 0.3μ in the PIN junction of an amorphous structure. It had the double feature of being able to be stretched to 1 to 3μ. Therefore, the optimum thickness of the I layer can be increased to 1.5 to 2.0 μm from 0.5 μm of an amorphous semiconductor, and the current as a photoelectric conversion device can be increased.

This laser annealing is performed at 3 in Figure 1C.
Active region 3 between 3 and 34 and between 33' and 34'
1, 11 only. The non-active region 4 is a high-resistance semiconductor, especially an amorphous semiconductor, and the semiconductor below 20 and the semiconductor 13 prevent leakage between the electrodes.

Furthermore, this laser annealing was carried out 1 to 2 mm inside of both ends of the element in the width direction, so as not to reach both ends. Therefore, amorphous semiconductor remains at both ends. In other words, the outer periphery of the active region is surrounded by a highly resistive amorphous semiconductor. By doing so, it was possible to prevent leakage between the upper and lower electrodes at the periphery of the active semiconductor, that is, a decrease in parallel resistance in terms of an equivalent circuit.

After this laser annealing, the plurality of second electrodes 39 and 38 were separated by cutting using a third LS to form third grooves 20 and isolate them.

This second conductive film 5 is made of metal and a transparent conductive oxide film (CTF). Its thickness is 300 ~
It was formed at 1500 Å.

As this CTF, a light-transmitting conductive film made of a non-oxide conductive film such as a chromium-silicon compound may be used.

These are electron beam evaporation method or sputtering method,
Including photo CVD method and photo plasma CVD method
Using the CVD method, it does not deteriorate the semiconductor layer, so
It was formed at a temperature below 250°C.

In this way, as shown in FIG. 1C, a photoelectric conversion device in which a plurality of elements 31 and 11 were connected in series through the connecting portion 4 could be manufactured.

FIG. 1D shows the present invention further completed as a photoelectric conversion device. That is, a silicon nitride film 21 with a thickness of 500 to 2000 Å is formed as a bonding film by a plasma vapor phase method or a photo plasma vapor phase method.
This further prevents leakage current between each element from occurring due to adsorption of moisture, etc.

Furthermore, external lead-out terminals 22, 22' are provided at the periphery.

In this way, for the irradiation light 10, on a substrate (10 cm x 10 cm) as in this example, each element has a width of 10 mm.
×92mm strip, and the width of the connection part is 200μ
Since the width of the external lead electrode part is 3 mm and the peripheral part is 4 mm, there are essentially 10 stages within 88 mm x 92 mm.

As a result, when the segment had a conversion efficiency of 11.3% (1.05 cm ² ), the panel had a conversion efficiency of 7.6% (theoretically 9.3%, but the effective conversion efficiency decreased due to the 9-stage series-connected resistance (AM1 [ 100mW/ ^cm2 〕))
We were able to achieve an output power of 6.3W.

Also, make this panel even larger, for example 40cm.
x 60 cm in series within a hard frame made of aluminum sash or a flexible frame made of carbon black to form a package.
It is possible to install a NEDO standard high power panel.

In addition, for panels that meet this NEDO standard, the top surface of the photoelectric conversion device of the present invention can be attached to the back surface of the glass substrate (opposite the irradiation surface) using Seaflex to increase mechanical strength against wind pressure, rain, etc. It is valid.

Example 2 This embodiment is illustrated according to the drawing in FIG.

In other words, as a metal foil substrate with an insulating coating, approximately
Substrate 1: The surface of a 100μ thick stainless steel foil is coated with polyimide resin to a thickness of 1.5μ using PIQ.
A length of 10 cm and a width of 10 cm were used.

Furthermore, SnO ₂ was formed on the top surface to a thickness of 1500 Å by sputtering.

After this, a first open groove was formed using a YAG laser with a spot diameter of 50 μm and an output of 0.5 W, controlled by a microcomputer at a scanning speed of 0.1 to 1 m/min (average 0.3 m/min).

The element regions 31 and 11 were 10 mm wide.

After this, the well-known PCVD method, photo-CVD method or photo-plasma CVD method was used to produce the
A non-single crystal semiconductor with one PIN junction was fabricated.

Since the light irradiation is from the upper second electrode side, N-type microcrystalline silicon (approximately 300 Å) semiconductor - I-type semiconductor (1.2μ) - P-type microcrystal is placed on the first electrode 2 on the substrate side. oxide Si semiconductor (300Å) - P-type Si _X C _1-X (approximately 50Å
x=0.2~0.3) Laminated with semiconductor.

Its total thickness was approximately 1.3μ.

After this, the first open groove was monitored on a television, and shifted 100μ from there to the first element 31 side, with a spot diameter of 50μ, average output of 0.5W, room temperature, frequency of 3KHz, and operation speed of 60cm/min. A second open groove 14 was created using LS.

After that, a light annealing process is performed on the I-type semiconductor through the upper P-type semiconductor using a pulse 25 of a 2 mmφ YAG laser (wavelength 0.5μ) 25 (in this case, the pulsed light is from the upper side in the opposite direction as shown in FIG. 1). I went to the layer. Then, the crystallization or orderliness of this microcrystalized P-type semiconductor layer and the I-type semiconductor layer below it was promoted, and a so-called polycrystalline region was formed.

The semiconductor thus obtained was immersed in 1/10 HF to remove the insulating oxide on the semiconductor surface, and the whole was then coated with ITO (CTF) to an average thickness of 700 Å by sputtering to form a second conductive film. 5 and connector 30 were constructed.

Furthermore, the third open groove 20 is similarly connected to the second groove by LS.
FIG. 1C was obtained by shifting the opening groove 14 to a depth of 100 μm toward the first element 31.

The average power of the laser beam was 0.5 W, and the other conditions were the same as those for producing the second open groove.

After the process shown in Figure 1C, the first electrode, semiconductor, and second electrode are all rectangularly scanned 4 mm inside the edge of the stainless steel substrate using a laser beam output of 1W, and the edge of the panel is aligned with the frame of the panel. prevents electrical short circuits.

Thereafter, a silicon nitride film with a thickness of 1000 Å was formed at a temperature of 250° C. by PCVD or photo plasma CVD to form a passivation film 21.

Then, nine 10mm wide elements are placed on a 10cm x 10cm panel.
I was able to make steps.

AM1 (100mw/cm ² ) as the effective efficiency of the panel
We were able to obtain an output of 8.7% and an output of 7.8W.

The effective area is ^82.8cm2 , 82.8% of the whole panel
was able to be used effectively.

The laser annealing in the present invention uses a wavelength of 0.53μ pulse width 30ns or 1.06μ (pulse width 70ns).
A YAG laser was used.

However, it has been effective to emit light with a wavelength of 500 (0.5 μm) to 5000 nm (5 μm) using another laser beam or a flash-shaped xenon lamp.

The embodiments of the present invention have been described regarding semiconductor devices, particularly photoelectric conversion devices. But the PIN with the same structure
It goes without saying that the present invention may also be applied to photo sensors and image sensors to which hydrogen or halogen elements are added and have an NIP structure.

"Effect" As shown in FIG.
(100 mw/cm ² )) is extremely effective. One example is the common amorphous
Compared to the deterioration characteristics 50 of the PIN type semiconductor, the present invention has been able to obtain a result 51 in which the deterioration of the I type semiconductor is extremely small even though it is thicker at 1.3 to 2 μm. 51 is Example 1, 52 is Example 2
It is a characteristic of

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of the present invention. FIG. 2 shows the light irradiation characteristics of a photoelectric conversion device without optical pulse annealing according to the present invention and a photoelectric conversion device using optical pulse annealing according to the present invention.

Claims (1)

[Claims] 1. A first electrode provided on a substrate having an insulating surface, a non-single crystal semiconductor doped with hydrogen or a halogen element and having a PIN junction provided closely on the electrode. , a semiconductor device in which a plurality of photoelectric conversion elements each having a second electrode provided on the semiconductor are connected in series at a connecting portion, the active region of the non-single crystal semiconductor being irradiated with strong light. By doing so, crystallinity of the semiconductor in the active region is promoted, and by not irradiating the semiconductor in the connection part with the strong light, the semiconductor in the connection part is made to maintain high resistance. A method for manufacturing a semiconductor device. 2. A method for manufacturing a semiconductor device according to claim 1, characterized in that a laser beam is used as the intense light.