JPS6184074A - semiconductor equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Field of Application of the Invention"
Relating to a photoelectric conversion device that generates a high voltage by electrically connecting in series a plurality of photoelectric conversion elements (simply referred to as elements) in which a non-single crystal semiconductor including an amorphous semiconductor having an N junction is provided on a substrate having an insulating surface. .

"Prior Art" Conventionally, amorphous semiconductors are known as non-single crystal semiconductors to which hydrogen or halogen elements are added. However, since such a semiconductor has an amorphous structure and does not actively use crystallinity, the thickness of the carrier depletion layer of the ■-type semiconductor layer in the PIN junction is as narrow as 0.3μ or less.
In addition, deterioration occurred due to light irradiation at A11 (100 mW/cm").

``Problems to be Solved by the Present Invention'' The present invention involves performing laser annealing on non-single crystal semiconductors containing hydrogen or halogen elements, including such amorphous semiconductors, to crystallize columnar grains having anisotropy. promotes formation, prevents deterioration due to light irradiation, and
It is characterized in that the depletion layer in the active region of the I-type semiconductor is widened to 1 J or more in the direction in which current flows in a photoelectric conversion device having an N junction.

Furthermore, the inactive semiconductor region constituting the connecting portion has a high resistance in a direction that crosses the grain boundaries of crystal grains many times, thereby preventing leakage between electrodes in this inactive region.

"Means for Solving the Problem" The present invention transmits a light-transmitting electrode from the side of the transparent electrode to the internal non-single-crystal semiconductor with pulsed strong light (with a pulse width of 10 to 1000 seconds),
(2) The crystallinity of the type semiconductor layer or the P or N type semiconductor layer adjacent thereto is promoted by segregating a large amount of hydrogen or a halogen element at the grain boundaries of the columnar grains and storing the hydrogen or halogen element inside the layer.

In particular, the present invention has a light absorption of 500 nm or more, generally 0.5 to 2μ, for example 0.53μ or 1.06μ.
Irradiating strong pulsed light from a YAG laser or a ruby laser with a wavelength of 0.69μ to promote the crystallinity of the I-type semiconductor as a whole or to a sufficiently deep region in the form of columnar grains with anisotropy. So-called optical annealing was performed.

Therefore, the light is transmitted through the transparent conductive film (Eg #3.
A wavelength of 500 nm or more was used, which is a wavelength that does not cause damage to 0 eV) and has a relatively small optical absorption coefficient of the semiconductor, that is, a wavelength of 500 nm or more that can perform optical annealing to a deep region.

In the present invention, the increase in electrical conductivity that accompanies the subsequent annealing must not interfere with isolation in the integrated structure. Therefore, in the method of the present invention,
The annealing was performed to have anisotropy such that the grain boundaries were parallel to the current flow only in the active semiconductor region, and the grain boundaries crossed the electric field in the non-active region. That is, the growth was made perpendicular to the substrate.

In the present invention, a YAG laser is applied to a non-single crystal semiconductor with laser light (Q-switch) in order to form a connection part for integration in an inactive region in a process that is performed simultaneously with, before, or after annealing. It was scribed and removed using light.

"Operation" Since the present invention uses the anisotropy of columnar grains, even if current can flow in the isolation region between each cell, the resistance is large because it is in the direction across the columnar grains, and sufficient isolation is required. I can do it. On the other hand, the current in PIN is in the direction along the columnar grains and does not cross grain boundaries. In addition, an optical confinement type cell is formed in which light is randomly given optical paths within one layer and crosses grain boundaries containing a large amount of hydrogen, which has a large optical absorption coefficient, many times. That is, it is effective to make the first and second electrodes on the back side uneven and to make the back electrode reflective. The present invention has these effects, and has the advantage that the manufacturing of an integrated photoelectric conversion device can be completed by adding light from the light irradiation surface side and completing the photo annealing process without any other extra steps. has.

The arrangement, size, and shape of elements in the device of the present invention are determined by design specifications. However, in order to simplify the content of the present invention, in the following detailed description, 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 will be described. 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, a laser beam for LS is applied to this specified position, for example, a YAG laser (focal path 111i140
m m ) is irradiated.

Further, it is moved at an operating speed of 0.05 to 5 m/min, for example, 30 cm/7 min, to create a subordinate relationship with the previous process.

In the present invention, when the substrate is a light-transmitting glass, or when a semiconductor is formed on a non-light-transmitting substrate, the upper surface is annealed with a laser beam of 500 nm or more (the energy density is lXl0' to I Xl0J/cm2, and the energy density during laser scribing is 5X106~5X10
7W/cm2), and by simply adding a laser annealing process to the conventional photoelectric conversion WiZ manufacturing process, the yield has been reduced to about 60% of the conventional method. It is an object of the present invention to provide an innovative method for manufacturing a photoelectric conversion device that can increase the conversion rate to 84%.

The details of the invention are shown below in accordance with the drawings.

"Example 1" FIG. 1 is a longitudinal sectional view of the photoelectric conversion element of the present invention.

In the drawings, a substrate with an insulating surface, for example a glass substrate 1
A piece (1) of 1.5 cm and a width of 2 cm was used.

Further, on this upper surface, a first conductive film (2) is formed over the entire surface.
A transparent conductive film having a thickness of 0.1 to 0.5 μm was formed. This conductive film had unevenness with a height difference of 0.1 μm.

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 (tin oxide indium) (500 to 500
(typically 500 to 1,500 people) was formed by a sputtering method or a spray method to form a first conductive film.

Thereafter, a non-single-crystal semiconductor layer to which hydrogen or a halogen element is added on the upper surface by a plasma CVD method, a photo-CvD method, or an LPCV-D method to form a non-single-crystal semiconductor that generates photovoltaic force upon light irradiation, that is, a PIN junction. (3)
The minimum oxygen concentration in type I semiconductor is 5 x 10111 cm-
3 or less, and the thickness is 0.3 to 5. Op is typically formed to have a thickness of 2.0 μm.

A typical example is when light is irradiated from the substrate side, so P
type (SixC1-xO<x<1) semiconductor (approximately 2
00A) - I-type amorphous or semi-amorphous silicon semiconductor (approximately 2.0 μ) - N-type microcrystal (approximately 50
A non-single-crystal semiconductor (3) having one PIN junction made of a semiconductor having a uniform thickness (0) was formed to have a uniform thickness.

In FIG. 1, a second conductive film (5) is further formed on this upper surface.
and a connector (30) was formed.

Further, in the method of the present invention, YAG that emits light at a wavelength of 500 nm or more (generally 530 nm or 1.06μ)
Also, an outline of a ruby pulsed light laser annealing apparatus and its method will be presented.

The structure to be irradiated is the one shown in FIG. 1 or the substrate on which the semiconductor (3) is laminated before forming the back electrode.

The irradiation area of the light source was set to 1 mm x 9 mm using an optical system using a ruby pulse laser beam.

In addition, in relation to the scan speed, the thickness was set to 1 mm, and in order to control the irradiation energy density, the thickness was set at 100 μ~
It may be varied up to 3 mm.

Here, a laser oscillator manufactured by CTC Comtic Training Co., Ltd. was used.

Furthermore, this laser beam is focused into a rectangular shape by a lens, has pulsed light (frequency 300Hz to 30KHz), and has a power output of 5KW.
/c (for width 11).

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

(Then, the total thickness of one layer in a non-single crystal semiconductor is
．． When using a wavelength of 7μ) or 0.53μ, it was possible to create a region that promotes crystallization of columnar grains in a region with a depth of 3,000 to 5,000 people, which is about half of that. The fact of this crystallization was found by performing laser Raman spectroscopy after this step.

In addition, since the annealing method of the present invention is a light pulse annealing, hydrogen or halogen elements that are already contained are less likely to be degassed to the outside during crystallization, and they are segregated at grain boundaries and are It can neutralize the unpaired bond in the field. In addition, since crystallinity or orderliness is promoted by photoannealing, photodegradation characteristics are reduced, and in addition, the width of the depletion layer in one layer in an amorphous semiconductor between PN can be reduced from 0.3μ in a PIN junction with an amorphous structure. It had the double feature of being able to be stretched to 1 to 3 μm in order to give it elasticity. Therefore, the optimum thickness of one layer can be increased from 0.5 μ of an amorphous semiconductor to 1.5 to 2.0 μ, and the current as a photoelectric conversion device can be increased.

Thus (the second conductive film (5) on the semiconductor shown in Figure 1)
) used metal and a transparent conductive oxide film (CTF).

The thickness of each layer was formed by 300 to 1,500 people, and the structure was an optical confinement type.

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, sputtering method, photo C
A CVD method including a vD method and a photo-plasma CVD method was used to form the semiconductor layer at a temperature of 250° C. or lower in order to prevent deterioration of the semiconductor layer.

Thus, for the irradiation light (10), on the substrate (3.5 mm x 3 cm) as in this example, 11.8% (1
, 05 cm2).

FIG. 2 is a configuration diagram illustrating the outline of the idea of the present invention.

Figure 2 (A) shows columnar grains (40) (only three locations are shown here) with a columnar diameter (41) of 0.1 to 2μ, generally less than 1μ as 5E)1 (scanning electron micrograph). Upon examination, it was found that the average grain size was 0.1-0.15μ, and they grew vertically.

This energy hand width is shown in Figure 2 (B), (C),
Shown in (D) and (E). In other words, Fig. 2 (B) is the second
This is a case in which no electric field is applied in the vertical direction at the center of the B-Bo columnar grain in FIG. In (C), holes (42) and electrons (43) are drifting due to the electric field. (D)
shows the energy hand in the cross section of the columnar grain at "A-to" in the lateral direction.

Then, electrons (42') and holes (43') generated by light irradiation undergo photo-electrical conversion in the region where a large amount of hydrogen exists at the grain boundary, and generate carriers (42) and (42'').

The carriers drift to a more stable level inside the columnar grains. Therefore, carriers can be drifted in the center of the columnar grains, which are separated by the grain boundaries where most of the recombination centers are present.

On the other hand, as shown in FIG. 2(E), an electric field is applied across the grain boundaries in the isolation region of the connection portion in the integrated structure. At this time, the grain boundaries (45) act as a barrier, making it difficult for leakage current to flow. That is, when attempting to integrate a photoelectric conversion device, columnar grains may be grown in a direction perpendicular to the substrate in order to prevent leakage current from flowing in the inactive region forming the connection portion.

In FIG. 2(F), hydrogen segregates at grain boundaries (45) of columnar grains (40) and becomes highly concentrated. Therefore, this grain boundary increases the optical Eg and has a large light absorption coefficient like an amorphous semiconductor.

This shows that it is important for light to cross this grain boundary many times in order to efficiently perform light-to-electrical conversion with a small thickness.

Also, for these reasons, the diameter of the pillars of the semiconductor is smaller than the thickness of the intrinsic or substantially intrinsic semiconductor, which is 0.1 to 5 μ, and is generally 0.05 to 0.2 μ. is valid.

If it is more than this, the carriers generated at the grain boundaries will drift into the P or N layer G before drifting into the interior of the columnar grains, and this will not be carried out sufficiently, which means that the purpose of raising the barrier with hydrogen at the grain boundaries will be lost. It will decrease.

In FIG. 3, (15) and (16) indicate the electrical conductivity in the vertical direction and the electrical conductivity in the lateral direction, respectively.

The initial value in each graph is the optical conductivity (15) in the structure of an amorphous semiconductor doped with hydrogen.
(17) and dark conductivity (16), (18). The next plot shows the characteristics after polycrystallization by performing ruby laser annealing on the amorphous semi-quartet, and the third plot shows the electrical conductivity after irradiation with light irradiation (AMI) for 2 hours. Furthermore, the fourth measurement point shows the characteristics after thermal annealing at 150° C. for 2 hours.

It is clear from these results that the electrical conductivity in the vertical direction improves by approximately three times due to photoannealing, but the electrical conductivity in the horizontal direction across grain boundaries, shown in (17), increases by approximately 3 times. It decreases to 1710.

In addition, photodeterioration (Stebler-Lonski effect) is observed in the electrical conductivity characteristics in the lateral direction due to hydrogen, oxygen, etc. present at the grain boundaries, but there is virtually no change in the electrical conductivity in the vertical direction. , is extremely stable.

Example 2 FIG. 4 is a longitudinal sectional view showing the manufacturing process of the present invention.

The manufacturing process of the film was carried out in the same manner as in Example 1.

That is, in the drawing, a substrate having an insulating surface, for example, a glass substrate (1), whose length is in the left-right direction in the drawing) 1
0 cm and a width of 10 cm. Further, on this upper surface, a first conductive film (2) is formed to transmit light over the entire surface.

A conductive film (2) was formed with a thickness of 0.1 to 0.5 μm and an uneven pattern.

After this, a YAG laser (wavelength 0.
53 μ (30 ns during pulse) Average output 0.3 to IW (focal length 40 mm) by processing machine (Nippon Denki type)
is added, a laser beam with a diameter of 5 mm φ is focused, a spot diameter of 20 to 70 μφ is typically controlled by a microcomputer, and the laser beam is irradiated from above. Open groove (13
), and each active element region (31), (11,
), a first electrode (15) was produced by laser scribing (referred to as LS).

The openings (13) formed by LS had a width of about 50 μm and a length of 10 cm, and the depths were completely cut and separated to form the first electrodes.

(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.

At this time, the semiconductor filled in the first semiconductor (13) is of a high resistance type, and isolation must be performed.

After this, plasma CVD method, Fol-CVD method is applied to this upper surface.
method or LPCV D method to form a non-single crystal semiconductor layer (3) with a thickness of 0.5 to 5.0 μm, typically 2.0 μm, as in the example.
It was formed to a thickness of μ.

Furthermore, as shown in Figure 4 (B), the first lecture (1
A second opening (14) was formed over the left side (first element side) of 3) by the second LSI process.

In this drawing, the first and second openings (13), (M
) are shifted by 100μ.

The second open groove (18) thus exposed the side or top surface (8), (9) of the first electrode.

Furthermore, the present invention provides a transparent conductive film (1) of the first electrode (2).
Although only the surface of 5) may be exposed, in order to improve production and yield, it is recommended that the laser beam be 0.1 to 0.8
W was a little too strong, so the entire depth of this first electrode (15) was removed. However, even if the connector (30) with the second electrode (38) in FIG. Oxide-oxide contact (tin oxide)
ITO contact), and no Kl barrier was formed at the interface, so there was no practical problem.

In FIG. 4, as shown in FIG. 4(C), a second conductive film (5) and a connector (30
) was formed.

・This second conductive film (5) is made of metal and a transparent conductive oxide film (
CTF) was used. Its thickness is 300~1
500 people formed it.

Furthermore, the ruby pulse light laser annealing which emits light with a wavelength of 500 nm or more in the method of the present invention was performed in the same manner as in Example 1.

That is, the substrate to be irradiated is shown in FIG. 4(B) or (C).

The same procedure as in Example 1 was carried out using the structure before or after forming the second light-transmitting electrode (5) as the target substrate in the photo-annealing process.

Thus, although not shown in the drawings, optical annealing (25
) was performed from the light irradiation side to form an I-type semiconductor on the semiconductor having columnar grains in the vertical direction.

At this time, the inactive area (34) (33'
) are the first elements of elements (31) and (11).
In order to achieve isolation between the electrodes, the columnar grains were grown perpendicularly to the substrate, crossing them many times.

After this laser annealing, a third LS was used to cut and separate the plurality of second electrodes (39) and (38) to form a third electrode (20) and isolate them.

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

Thus, as shown in FIG. 4(C), a plurality of elements (
31) and (11) were connected in series at the connection part (4) to create a photoelectric conversion device.

FIG. 4(D) shows the present invention further completed as a photoelectric conversion device. That is, as a passivation film, a silicon nitride film (21) is uniformly formed to a thickness of 500 to 2,000 layers by a plasma vapor phase method or a photo plasma vapor phase method, and the leakage current between each element is caused by adsorption of moisture, etc. This further prevented the outbreak.

Furthermore, external lead-out terminals (22) and (22') were provided at the periphery.

Thus, for the irradiation light (10), on a substrate (10 cm x LO cm) as in this example, each element has a width of 1
It is provided in a strip shape of 0 mm x 92 mrrl, and furthermore, the width of the 200 μm external extraction electrode part in the connecting part is 3 mm, and the peripheral part is 4 mm.
It has a 0 stage.

The result was 8.3% on the panel (theoretically 9.6%
However, the effective conversion efficiency decreased due to the 11-stage series-connected resistor (^old (100mW/cm2)), 6.
It was possible to maintain an output power of 7W.

Furthermore, make this panel larger, for example, 40cmX.
A 120cm x 40cm NE is packaged by combining two 60cm pieces in series within a hard frame made of aluminum sash or a flexible frame made of carbon black.
It is possible to provide DO standard high power panels.

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

The effective efficiency of the panel is AMI (100mW/cm
”), we were able to obtain 8.7%, cuff, and 8W.

The effective area is 82.8 cm”, and the total panel area is 82.8 cm”.
8% could be used effectively.

For laser annealing in the present invention, a YAG laser with a 0.53 μ pulse width of 30 ns or a ruby laser with a wavelength of 0.69 μ (pulse width 70 ns) was used.

However, this 500nm (0.5μ) ~ 5000nm (
It is effective to use another laser beam or a flash-shaped xenon lamp to emit light with a wavelength of 5 μm).

The embodiments of the present invention have been described regarding semiconductor devices, particularly photoelectric conversion devices that irradiate light from the glass substrate side. However, this method can also be applied to a photoelectric conversion device in which irradiation is applied from above the substrate by coating a metal substrate with an insulating film and laminating a lower electrode, a semiconductor, and an upper electrode on the upper surface. In addition, it goes without saying that the present invention may be applied to photosensors and image sensors to which hydrogen or halogen elements are added and have a PTN or NIP structure.

"Effect" As shown in FIG.
mw/cm2)) effect. As an example, compared to the deterioration characteristics of a general amorphous PIN type semiconductor (50), in the case of an I type semiconductor, 1
．． In spite of the thickness of 0 to 5 μm, the present invention was able to obtain results (51) in which the deterioration was extremely small. (
51) is the characteristic of Example 1, and (52) is the characteristic of Example 2.

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal cross-sectional view of a photoelectric conversion device of the present invention. FIG. 2 shows the columnar grains and the corresponding energy hand obtained according to the invention. FIG. 3 shows the characteristics obtained with the present invention. FIG. 4 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of the present invention. FIG. 5 shows the light irradiation cheek characteristics of a photoelectric conversion device without optical pulse annealing according to the present invention and a photoelectric conversion device subjected to optical pulse annealing according to the present invention.

Claims (3)

[Claims] 1. A substrate having an insulating surface has a first electrode, a non-single crystal semiconductor doped with hydrogen or a halogen element having a PIN junction in close contact with the electrode, and a second electrode on the semiconductor. A semiconductor device including a plurality of photoelectric conversion elements connected in series at a connecting portion, characterized in that the intrinsic or substantially intrinsic type I semiconductor has columnar grains in part or all in a direction perpendicular to the substrate. semiconductor device. 2. 2. A semiconductor device according to claim 1, wherein the first and second electrodes have uneven surfaces, and the back electrode is provided with a reflective electrode. 3. 2. A semiconductor device according to claim 1, wherein the inactive region constituting the connecting portion is provided with a high resistance region in a direction that crosses grain boundaries of crystal grains many times.