JP5084784B2 - Microcrystalline silicon film manufacturing apparatus and microcrystalline silicon film manufacturing method - Google Patents

Description

  The present invention relates to a microcrystalline silicon film manufacturing apparatus and a microcrystalline silicon film manufacturing method.

  Conventionally, thin film solar cells have adopted a tandem structure in which a plurality of photoelectric conversion layers (semiconductor layers) made of materials with different band gaps are stacked on a translucent insulating substrate in order to effectively use the solar spectrum widely. Yes. In particular, in the case of a silicon-based thin-film solar cell, an amorphous silicon cell and a microcrystalline silicon cell are often laminated as a semiconductor layer. Here, each cell has a structure in which a p-type film, an i-type film, and an n-type film are stacked. The i-type film is a power generation layer, and the p-type film and the n-type film are layers for forming a built-in electric field. is there.

In microcrystalline silicon cells, it is desirable to apply a moderately crystallized film as the i-type film of the power generation layer. Usually, a microcrystalline silicon film is often formed by a plasma chemical vapor deposition (PE-CVD) method using silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) as raw materials, and its crystallization rate is It has been reported that the flow rate ratio of raw material gas (H ₂ / SiH ₄ ) and the high frequency power applied during film formation vary greatly. In fact, many research institutions and companies are trying to realize microcrystalline silicon films with a target crystallization rate by adjusting and optimizing these film forming parameters.

  When a microcrystalline silicon film is grown under a certain condition by a plasma CVD method, a low-crystalline amorphous layer is first formed on a substrate with a thickness of about 100 nm (incubation layer) at the initial stage of film formation, and then a crystal is formed thereon. It has been confirmed that a film with a high conversion rate grows gradually. Usually, such an incubation layer has a high defect density in the film, and when applied to a power generation layer of a solar cell, it traps carriers (electrons and holes) generated by light irradiation and loses the generated current. Is concerned.

  For this reason, in the conventional i-type microcrystalline silicon film formation, the initial layer is formed to a thickness of about 100 nm under the condition that the crystallization rate is high, and then a two-stage process is performed in which a bulk part (˜2 μm) is formed under normal conditions. Studies have been made on a film forming method for suppressing the formation of an incubation layer (for example, see Non-Patent Document 1).

In addition, during the deposition of i-type microcrystalline silicon, the density of radical species (SiH _x , H) in the film formation chamber was measured in-situ (from the observation window provided on the inner wall of the film formation chamber, A film forming method in which feedback is applied to film forming conditions (SiH ₄ , H ₂ supply amount, applied power) so that the radical density is constant from the start to the end of film formation. Studies have been made to suppress the formation of the incubation layer by realizing a film forming apparatus (see, for example, Patent Document 1).

JP-A-10-212197

A.H.M.Smets, T.Matsui, and M.Kondo, `` High-rate deposition of microcrystalline silicon p-i-n solar cell in the high pressure depletion regime '', JOURNAL OF APPLIED PHYSICS 104, 034508 (2008)

  However, in the method for producing microcrystalline silicon in Non-Patent Document 1 described above, the film formation conditions of the initial layer are fixed before film formation, and no feedback is applied during the process. There was a problem that the battery characteristics varied from lot to lot.

  Moreover, in the thin film manufacturing apparatus in Patent Document 1 described above, an observation window for monitoring radical emission intensity is provided on the inner wall of the film forming chamber. During film formation, film deposition progresses on the window surface and the window becomes cloudy. There is a problem that the emission intensity cannot be measured accurately. If the radical density cannot be measured accurately, automatic feedback control of film forming conditions cannot be performed appropriately. Further, even if an attempt is made to suppress film deposition by flowing a purge gas (inert gas) over the window surface, it is impossible to completely prevent fogging of the window.

  Usually, a thin film photovoltaic cell is formed on a large-area glass substrate having a side of 1 meter or more. In the microcrystalline silicon film manufactured by the film forming apparatus and the film forming method described in Non-Patent Document 1 and Patent Document 1, the formation of the incubation layer at the initial stage of film formation is uniformly uniform within the surface on such a large-area glass substrate. Is impossible to achieve. When the crystallization ratio of the initial layer of film formation varies within the substrate surface, the power generation efficiency of the produced solar cells also varies within the substrate surface, and there is a concern that the yield of products may be directly reduced.

  The present invention has been made in view of the above, and an object thereof is to obtain a microcrystalline silicon film manufacturing apparatus and a microcrystalline silicon film manufacturing method capable of forming a microcrystalline silicon film having a stable film quality with a high yield. To do.

  In order to solve the above-described problems and achieve the object, a microcrystalline silicon film manufacturing apparatus according to the present invention has a light-transmitting target substrate held on a substrate stage, and the target substrate is manufactured. The source gas is supplied toward the film surface, plasma of the source gas is generated, the source gas is decomposed by the plasma, and deposited on the film surface to form a microcrystalline silicon film. A film forming chamber; and a measuring means for measuring the crystallization rate of the microcrystalline silicon film through the substrate stage and the substrate to be processed by Raman spectroscopy from the opposite side of the substrate to be processed in the substrate to be processed. It is characterized by providing.

  According to the present invention, there is an effect that a microcrystalline silicon film having a substantially uniform crystallization rate in the film thickness direction and having a stable film quality can be formed with a high yield.

FIG. 1 is a schematic diagram for explaining the structure of the inside of a film forming chamber of a microcrystalline silicon film manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a characteristic diagram showing an example of a Raman scattering spectrum of the microcrystalline silicon film manufactured by the microcrystalline silicon film manufacturing apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram showing an example of a cross-sectional TEM (Transmission Electron Microscope) image of a microcrystalline silicon film manufactured by a conventional microcrystalline silicon film manufacturing apparatus. FIG. 4 is a characteristic diagram showing an example of a profile with respect to the film thickness direction of the crystallization rate of a microcrystalline silicon film manufactured by a conventional microcrystalline silicon film manufacturing apparatus. FIG. 5 is a characteristic diagram showing the relationship between the crystallization rate of the microcrystalline silicon film and the gas supply amount ratio γ (H ₂ / SiH ₄ ) between the silane gas and the hydrogen gas during film formation. FIG. 6 is a characteristic diagram showing the relationship between the crystallization rate of the microcrystalline silicon film and the high-frequency power applied during film formation. FIG. 7 is a characteristic diagram showing an example of a profile of the gas supply amount with respect to the process elapsed time when the microcrystalline silicon film is formed by the microcrystalline silicon film manufacturing apparatus according to the first embodiment of the present invention. FIG. 8 is a characteristic diagram showing an example of a profile of the crystallization rate of the microcrystalline silicon film manufactured by the microcrystalline silicon film manufacturing apparatus according to the first embodiment of the present invention with respect to the process elapsed time. FIG. 9 is a schematic diagram showing a cross-sectional structure of the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. FIG. 10 is a characteristic diagram showing an example of a profile of the applied high-frequency power with respect to the process elapsed time when the microcrystalline silicon film is formed by the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. FIG. 11 is a characteristic diagram showing an example of a profile of the crystallization rate of the microcrystalline silicon film manufactured by the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention with respect to the process elapsed time. FIG. 12 is a diagram showing an example of a cross-sectional TEM image of a microcrystalline silicon film manufactured by the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. FIG. 13 shows electrical characteristics (voltage-current characteristics) of a thin-film solar cell (microcrystalline silicon cell) of a module having a power generation layer formed using the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. It is a characteristic view which shows an example. FIG. 14A is a plan view illustrating a schematic configuration of a module having a power generation layer formed by using the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. FIG. 14-2 is a key for explaining a cross-sectional structure of a thin-film solar battery cell (microcrystalline silicon cell) having a power generation layer formed by using the microcrystalline silicon film manufacturing apparatus according to the second embodiment of the present invention. FIG. FIG. 15 is a schematic diagram showing the structure of a microcrystalline silicon film manufacturing apparatus according to Embodiment 3 of the present invention. FIG. 16 is a characteristic diagram showing an in-plane distribution of measured values of the crystallization rate of an i-type microcrystalline silicon film manufactured using a conventional microcrystalline silicon film manufacturing apparatus. FIG. 17 is a characteristic diagram showing an in-plane distribution of measured values of the crystallization rate of an i-type microcrystalline silicon film manufactured using the microcrystalline silicon film manufacturing apparatus according to the third embodiment of the present invention. FIG. 18 is a characteristic diagram showing an in-plane distribution of power generation efficiency of a thin-film solar cell in which a power generation layer is manufactured using a conventional microcrystalline silicon film manufacturing apparatus. FIG. 19 is a characteristic diagram showing an in-plane distribution of power generation efficiency of a thin-film solar cell in which a power generation layer is manufactured using the microcrystalline silicon film manufacturing apparatus according to the third embodiment of the present invention.

  Embodiments of a microcrystalline silicon film manufacturing apparatus and a microcrystalline silicon film manufacturing method according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram for explaining the structure of the inside of a film forming chamber of a microcrystalline silicon film manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 1 shows a state in which a microcrystalline silicon film is formed by a microcrystalline silicon film manufacturing apparatus. The apparatus for producing a microcrystalline silicon film according to the first embodiment can be used for forming an i-type microcrystalline silicon film (power generation layer) of a thin-film solar battery cell (microcrystalline silicon cell).

  As shown in FIG. 1, a substrate stage 1 that is a holding member that holds a translucent insulating substrate 2 that is a substrate to be processed is installed inside a film forming chamber R having a substantially rectangular parallelepiped shape. The substrate stage 1 is grounded. A translucent insulating substrate 2 is held on the substrate stage 1 so that the film-forming surface is horizontal and upward.

In addition, a shower head 4 for distributing and supplying the source gas to the upper region of the substrate stage 1 is provided on the upper surface of the film forming chamber R. The shower head 4 is connected to a gas supply pipe 3 for sending the raw material gas into the film forming chamber R. A silane gas (SiH ₄ ) supply mass flow 16 and a hydrogen gas (H ₂ ) supply mass flow 17 are connected to the gas supply pipe 3, and a controller 18 supplies a silane gas (SiH ₄ ) supply mass flow 16 and hydrogen gas ( H ₂ ) The supply mass flow 17 is automatically controlled to control the supply amount of the source gas into the film forming chamber R. That is, the controller 18 functions as a source gas supply amount control means. Each mass flow is connected to a gas supply source such as a gas cylinder (not shown). The film forming chamber R can be evacuated by an exhaust unit (not shown).

  A power source 5 is connected to the shower head 4 via a power line 19, and plasma 6 is interposed between the translucent insulating substrate 2 and the shower head 4 by applying high frequency power from the power source 5 to the shower head 4. Is generated. The source gas dispersed from the shower head 4 is decomposed by the plasma 6 to generate a film-forming precursor, which is deposited on the light-transmitting insulating substrate 2 and deposited on the upper surface of the light-transmitting insulating substrate 2. Will grow.

  A plurality of holes 8 are provided inside the substrate stage 1 on the upper surface side (side holding the translucent insulating substrate 2). Inside the holes 8 are laser irradiation for Raman spectroscopy and Raman scattered light. A light receiving lens 9 is installed. A Raman laser light source 10 is connected to the lens 9 via an optical fiber line 11. The Raman laser light source 10 emits a laser beam 14 for Raman spectroscopy. The laser light 14 emitted from the Raman laser light source 10 is incident on the lens 9 through the optical fiber line 11, passes through the monitor window 12 for Raman spectroscopic evaluation provided in the upper portion of the hole 8, and the transparent insulating substrate 2. The microcrystalline silicon film 7 is irradiated from the back side (lower surface side).

  In the monitor window 12, the Raman scattered light 15 generated by irradiating the microcrystalline silicon film 7 with the laser light 14 passes in the opposite direction to the laser light 14, passes through the lens 9, the optical fiber 11, and the spectrometer 13. Is incident on.

  Next, a process for forming a microcrystalline silicon film by the apparatus for manufacturing a microcrystalline silicon film according to the first embodiment will be described. In order to perform the film forming process of the microcrystalline silicon film, first, the translucent insulating substrate 2 is held on the substrate stage 1 so that the film forming surface is horizontal and upward, and then an exhaust unit (not shown). Thus, the film forming chamber R is evacuated, and the film forming chamber R is evacuated.

Then, silane gas through the gas supply pipe 3 (SiH ₄₎ for supplying a mass flow 16 hydrogen gas _{(H 2)} film chamber silane gas _(SiH 4) in the interior of the R from the supply mass flow 17, of hydrogen gas _{(H 2)} The source gas is fed, and the source gas is distributed and supplied to the upper region of the substrate stage 1, that is, the upper surface of the translucent insulating substrate 2 on the substrate stage 1 through the shower head 4. The supply amount of the raw material gas into the film forming chamber R is controlled by the controller 18 automatically controlling the silane gas (SiH ₄ ) supply mass flow 16 and the hydrogen gas (H ₂ ) supply mass flow 17.

  High frequency power is applied to the shower head 4 from a power source 5, and thereby plasma 6 is generated between the substrate stage 1 (translucent insulating substrate 2) and the shower head 4. The source gas dispersed from the shower head 4 is decomposed by the plasma 6 to generate a film-forming precursor, which is deposited on the light-transmitting insulating substrate 2 and deposited on the upper surface of the light-transmitting insulating substrate 2. Will grow.

  In this embodiment, after the formation of the microcrystalline silicon film 7 is started as described above, Raman spectroscopic evaluation of the microcrystalline silicon film 7 is performed during the film formation. That is, when the laser beam 14 is emitted from the Raman laser light source 10 for Raman spectroscopy, the laser beam 14 is incident on the lens 9 through the optical fiber 11 and passes through the monitor window 12 provided in the upper portion of the hole 8 to be transmitted. The microcrystalline silicon film 7 is irradiated from the back side (lower surface side) of the optical insulating substrate 2.

  Here, the Raman scattered light 15 generated by irradiating the microcrystalline silicon film 7 with the laser light 14 is received by the spectroscope 13 from the monitor window 12 through the lens 9 and the optical fiber 11, as shown in FIG. A stable Raman spectrum. FIG. 2 is a characteristic diagram showing an example of a Raman scattering spectrum of the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the first embodiment.

In FIG. 2, the peak of the Raman spectrum caused by the crystalline silicon component appears at a wavelength of 520 cm ⁻¹ (I ₅₂₀ ), and the component caused by amorphous silicon appears at a wavelength of 480 cm ⁻¹ (I ₄₈₀ ). the peak intensity ratio _I 520 _{/ I 480} is defined as the crystallization ratio _I 520 _{/ I 480.} Here, the spectrometer 13 is connected to a silane gas (SiH ₄ ) supply mass flow 16 and a hydrogen gas (H ₂ ) supply mass flow 17 via a controller 18. The controller 18 calculates and monitors the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 based on the Raman scattering spectrum of the microcrystalline silicon film 7 read by the spectroscope 13 and monitors the crystal read by the spectroscope 13. The silane gas (SiH ₄ ) supply mass flow 16 and the hydrogen gas (H ₂ ) supply mass flow 17 are automatically controlled so that the measured value of the conversion rate I ₅₂₀ / I ₄₈₀ approaches the target value. Give feedback on gas supply. That is, in the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the amount of material gas supply, which is a film forming parameter, is automatically controlled during film formation. As a result, the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial film formation layer can be increased, and a microcrystalline silicon film having a uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction without forming an incubation layer. Can be formed.

  FIG. 3 is a diagram showing an example of a cross-sectional TEM (Transmission Electron Microscope) image of a microcrystalline silicon film 23 (film thickness: ˜2 μm) formed on a glass substrate 21 by a conventional microcrystalline silicon film manufacturing apparatus. As can be seen from FIG. 3, a thin amorphous silicon layer 22 (incubation layer) of about 500 nm is formed between the microcrystalline silicon film 23 and the glass substrate 21. That is, the incubation layer is formed at the initial stage of film formation.

FIG. 4 is a characteristic diagram showing an example of a profile with respect to the film thickness direction of the crystallization rate I ₅₂₀ / I ₄₈₀ of a microcrystalline silicon film manufactured by a conventional microcrystalline silicon film manufacturing apparatus. In FIG. 4, the change in the crystallization ratio I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film having a thickness of 50 nm to 1000 nm manufactured on the glass substrate by changing the film forming time to change the film thickness of the microcrystalline silicon film. Is shown.

FIG. 4 shows that the film having a thickness of 50 nm to 400 nm is an amorphous film having a crystallization ratio I ₅₂₀ / I ₄₈₀ of 1.0 or less. Further, FIG. 4 shows that the crystallization rate I ₅₂₀ / I ₄₈₀ monotonically increases from the vicinity of the film thickness of 400 nm, and that the crystallization rate I ₅₂₀ / I ₄₈₀ increases as the film grows. I understand. That is, it can be seen that the crystallization ratio I ₅₂₀ / I ₄₈₀ increases from the glass substrate in the film thickness direction.

FIG. 5 shows the crystallinity I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film and the gas supply amount ratio γ (H ₂ / SiH ₄ ) between the silane gas (SiH ₄ ) and the hydrogen gas (H ₂ ) during film formation. It is a characteristic view which shows the relationship of these. In FIG. 5, the crystal of the microcrystalline silicon film manufactured by changing the gas supply amount ratio γ (H ₂ / SiH ₄ ) between the raw material silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) in the range of 30-80. Conversion rate I ₅₂₀ / I ₄₈₀ . FIG. 6 is a characteristic diagram showing the relationship between the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film and the high-frequency power applied during film _formation . FIG. 6 shows the behavior of the crystallization ratio I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film manufactured by changing the high frequency power P applied to the plasma during the formation of the microcrystalline silicon film in the range of 120 W to 300 W. Yes.

As shown in FIGS. 5 and 6, the crystallization rate I ₅₂₀ / I ₄₈₀ shows a monotonically increasing behavior as the gas supply ratio γ and the high frequency power P increase, and the crystal of the microcrystalline silicon film It can be seen that the conversion rate I ₅₂₀ / I ₄₈₀ can be adjusted by changing the gas supply amount ratio γ and the high frequency power P of the film forming parameter.

7 shows gas supply amounts (silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) supply amounts with respect to process elapsed time when the microcrystalline silicon film manufacturing apparatus according to the first embodiment forms a microcrystalline silicon film. ) Is a characteristic diagram showing an example of a profile. In this example, after the elapse of t ₀ (sec) from the start of film formation, based on the measured value of the crystallization rate I ₅₂₀ / I ₄₈₀ read by the spectroscope 13 by Raman spectroscopy measurement on the back surface of the microcrystalline silicon film 7. The controller 18 automatically controls the silane gas (SiH ₄ ) supply mass flow 16 and the hydrogen gas (H ₂ ) supply mass flow 17 to automatically increase the supply amount of silane gas (SiH ₄ ), and to supply hydrogen gas (H ₂ ). Control to reduce the supply amount is performed, and increase adjustment of the crystallization ratio I ₅₂₀ / I ₄₈₀ of the film to be manufactured is achieved.

FIG. 8 is a characteristic diagram showing an example of a profile with respect to the process elapsed time of the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the first embodiment. FIG. 8 also shows an example of a profile with respect to the process elapsed time of the crystallization ratio I ₅₂₀ / I ₄₈₀ of a microcrystalline silicon film manufactured by a conventional microcrystalline silicon film manufacturing apparatus. In FIG. 8, the plot X shows a file of the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 produced by the microcrystalline silicon film manufacturing apparatus according to the first embodiment, and the solid line Y shows the conventional microscopic silicon film 7. The profile of the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film manufactured by the crystalline silicon film manufacturing apparatus is shown.

From FIG. 8, the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the first embodiment has a high crystallization rate I ₅₂₀ / I ₄₈₀ from the initial stage of film formation, and with the lapse of time of the process. Thus, it can be seen that a microcrystalline silicon film having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction can be produced.

On the other hand, in film formation by a conventional microcrystalline silicon film manufacturing apparatus, a microcrystalline silicon film having a low crystallization rate I ₅₂₀ / I ₄₈₀ is formed at the initial stage of film formation, and then gradually crystallizes with the passage of process time. The conversion rate I ₅₂₀ / I ₄₈₀ is increasing. That is, in the conventional microcrystalline silicon film manufacturing apparatus, the crystallization rate I ₅₂₀ / I ₄₈₀ is changed from a low film to a high film in the film thickness direction, and the distribution of the crystallization rate I ₅₂₀ / I _{480 in} the film thickness direction is changed. It can be seen that a large microcrystalline silicon film is produced.

When the microcrystalline silicon thin film having a thickness of 2 μm was actually manufactured using the microcrystalline silicon film manufacturing apparatus according to the first embodiment described above, the surface of the microcrystalline silicon film 7 was formed from the vicinity of the surface of the translucent insulating substrate 2. The rate of change in the film thickness direction of the crystallization rate I ₅₂₀ / I _{480 up} to 1% can be suppressed to 1% or less (near the substrate: ~ 3.90, film surface: ~ 4.05, target value: 4.00). It was. This is a change in the crystallization rate I ₅₂₀ / I _{480 in} the film thickness direction of the microcrystalline silicon film when the film is formed by a conventional microcrystalline silicon film manufacturing apparatus (near substrate: ~ 0.40, film surface: ~ 4). .05) is about 10 times lower.

  In addition, when continuous film formation was performed on 100 translucent insulating substrates 2 using the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the intensity of the Raman scattered light 15 received is: Almost no change (attenuation) was seen. That is, even if continuous film formation is performed on 100 translucent insulating substrates 2, no monitoring failure due to film adhesion to the monitor window 12 occurs, and automatic control with high-precision feedback is performed. I was able to.

As described above, in the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film formed on the translucent insulating substrate 2 is set in-situ. It has a configuration for monitoring and evaluating by Raman spectroscopy. By providing such a configuration, the laser beam 14 was irradiated from the back side of the translucent insulating substrate 2 placed on the substrate stage 1 during film formation, and generated on the back side of the microcrystalline silicon film 7. The Raman scattered light 15 is measured (Raman spectroscopy), and the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 can be monitored through the translucent insulating substrate 2. By using Raman spectroscopy, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 having a film thickness of 100 nm or less can be accurately evaluated even through the translucent insulating substrate 2.

Then, the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 (≦ 100 nm) is monitored, and based on the information of the obtained crystallization rate I ₅₂₀ / I ₄₈₀ , the crystallization rate I ₅₂₀ / I. _The film forming parameters (feed amount of raw material gas) are adjusted by automatic control by feeding back the film forming conditions so that ₄₈₀ becomes the target value. Thereby, it is possible to increase the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial layer of film formation, and without forming an incubation layer, microcrystalline silicon having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction. A film can be formed.

In the microcrystalline silicon film manufacturing apparatus according to the first embodiment, since the monitor window 12 through which the Raman scattered light 15 passes is located on the back side of the translucent insulating substrate 2, the source gas comes in. No film deposition occurs. Therefore, automatic control of film forming condition feedback can be appropriately performed without reducing the accuracy of automatic control of film forming condition feedback during film formation as in the conventional microcrystalline silicon film manufacturing apparatus, A microcrystalline silicon film with a substantially uniform crystallization ratio I ₅₂₀ / I ₄₈₀ in the film thickness direction can be formed with high yield.

  Therefore, according to the microcrystalline silicon film manufacturing apparatus according to the first embodiment, a microcrystalline silicon film having a uniform film quality and a stable film quality can be formed with a high yield.

Further, in the method for manufacturing a microcrystalline silicon film according to the first embodiment, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 formed on the translucent insulating substrate 2 is transmitted in-situ. and Raman spectrometry was monitored from the back side of sexual insulating substrate 2, based on the obtained information of the crystallization ratio _I 520 _{/ I 480,} form a film having a crystallization ratio _I 520 _{/ I 480} is the target value The film forming parameters (feed amount of raw material gas) are adjusted by automatic control with feedback on the conditions. As a result, the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial film formation layer can be increased, and a microcrystalline silicon film having a substantially uniform crystallization rate in the film thickness direction can be formed with good yield without forming an incubation layer. can do.

Embodiment 2. FIG.
FIG. 9 is a schematic diagram illustrating a cross-sectional structure of the microcrystalline silicon film manufacturing apparatus according to the second embodiment. FIG. 9 shows a state in which the microcrystalline silicon film is formed by the microcrystalline silicon film manufacturing apparatus. The microcrystalline silicon film manufacturing apparatus according to the second embodiment is configured such that the controller 18 is connected to the power source 5 in the microcrystalline silicon film manufacturing apparatus according to the first embodiment shown in FIG. With this configuration, it is possible to automatically control the power supply 5 based on the measured value of the crystallization rate I ₅₂₀ / I ₄₈₀ read by the spectroscope 13 and to provide feedback on the high frequency power applied to the plasma. That is, the controller 18 also functions as an applied power control unit.

FIG. 10 is a characteristic diagram showing an example of a profile of the applied high frequency power applied to the plasma with respect to the process elapsed time when the microcrystalline silicon film is formed by the microcrystalline silicon film manufacturing apparatus according to the second embodiment. In the example shown in FIG. 10, immediately after the start of film _formation , the controller 18 automatically controls the power source 5 based on the measured value of the crystallization rate I ₅₂₀ / I ₄₈₀ in the spectroscope 13 by Raman spectroscopic measurement. The high frequency power to be set is automatically set to a high value, and an increase adjustment of the crystallization ratio I ₅₂₀ / I ₄₈₀ of the film to be manufactured is achieved. Further, in the example shown in FIG. 10, after t ₀ (sec) has elapsed from the start of film _formation , when the measured value of the crystallization rate I ₅₂₀ / I ₄₈₀ in the spectroscope 13 exceeds (achieves) the target value, plasma is generated. Adjustment is made to reduce the high-frequency power to be applied.

FIG. 11 is a characteristic diagram showing an example of a profile with respect to the process elapsed time of the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the second embodiment. Here, the adjustment of the gas supply amount (the supply amount of silane gas (SiH ₄ ) and hydrogen gas (H ₂ )) shown in FIG. 7 and the adjustment of the applied high-frequency power shown in FIG. A silicon film is formed.

As shown in FIG. 11, the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the second embodiment has a substantially constant crystallization rate I ₅₂₀ / I ₄₈₀ from the initial stage of film formation. Compared with the microcrystalline silicon film 7 manufactured by the microcrystalline silicon film manufacturing apparatus according to the second embodiment shown in FIG. 8, the crystallization rate in the initial stage of film formation (0 (sec) to t ₀ (sec)) It can be seen that I ₅₂₀ / I ₄₈₀ is closer to the target value and is more constant with respect to the film formation time. That is, it can be seen that a substantially uniform microcrystalline silicon film can be manufactured in which the crystallization rate I ₅₂₀ / I ₄₈₀ is closer to the target value in the film thickness direction.

  FIG. 12 is a diagram showing an example of a cross-sectional TEM image of the microcrystalline silicon film 24 (film thickness: ˜2 μm) formed on the glass substrate 21 by the microcrystalline silicon film manufacturing apparatus according to the second embodiment. As can be seen from FIG. 12, the incubation layer as shown in FIG. 3 is not seen between the microcrystalline silicon film 24 and the glass substrate 21, and the microcrystalline silicon film 24 grows from directly above the glass substrate 21. I understand that That is, it can be seen that the incubation layer is not formed at the initial stage of film formation.

  FIG. 13 shows a thin film solar cell of a thin film solar cell module (hereinafter referred to as a module) 31 having a power generation layer (i-type microcrystalline silicon film) formed using the microcrystalline silicon film manufacturing apparatus according to the second embodiment. It is a characteristic view which shows the electrical characteristic (voltage-current characteristic: IV characteristic) of the cell (microcrystal silicon cell) C (Example). FIG. 14A is a plan view illustrating a schematic configuration of the module 31. FIG. 14-2 is a diagram for explaining a cross-sectional structure of the thin-film solar battery cell (microcrystalline silicon cell) C, and is a cross-sectional view of the main part in the line A-A ′ direction of FIG.

  As illustrated in FIGS. 14A and 14B, the module 31 according to the example includes a strip-shaped (rectangular) thin-film solar cell (microcrystalline silicon cell) formed on a translucent insulating substrate 32. A plurality of C are provided, and adjacent thin-film solar cells (microcrystalline silicon cells) C are electrically connected in series. The thin-film solar cell (microcrystalline silicon cell) C reflects light on the transparent insulating substrate 32, the transparent electrode layer 33 that is the first electrode layer made of a transparent conductive film, the photoelectric conversion layer 37, and light. A back electrode layer 38 that is a second electrode layer made of a conductive film is sequentially stacked.

  The photoelectric conversion layer 37 is a photoelectric conversion layer made of a microcrystalline silicon film having a pin junction, and as shown in FIG. 14-2, a p-type microcrystalline material that is a first conductive semiconductor layer from the transparent electrode layer 33 side. A p-type microcrystalline silicon film (μc-Si film) 34 as a semiconductor layer, an i-type microcrystalline silicon film (μc-Si film) 35 as an i-type microcrystalline semiconductor layer as a second conductivity type semiconductor layer, An n-type microcrystalline silicon film (μc-Si film) 36 is provided as an n-type microcrystalline semiconductor layer which is a three-conductivity type semiconductor layer. Here, the i-type microcrystalline silicon film (μc-Si film) 35 is formed of a microcrystalline silicon film formed using the microcrystalline silicon film manufacturing apparatus according to the second embodiment.

  Such a module 31 is manufactured as follows, for example. First, the transparent electrode layer 33 that is the first electrode layer is formed on the translucent insulating substrate 32. The transparent electrode layer 33 is laser scribed from the back side (the side where the transparent electrode layer 33 is not formed) of the translucent insulating substrate 32 so that an opening reaching the surface of the translucent insulating substrate 32 is formed. Patterning is performed.

  Subsequently, a P-type microcrystalline silicon film (μc-Si film) 34, an i-type microcrystalline silicon film (μc-Si film) 35, and an n-type microcrystalline silicon film (μc-Si film) 36 are deposited in this order. Thus, the photoelectric conversion layer 37 having a p-i-n junction is formed. Here, in forming the i-type microcrystalline silicon film (μc-Si film) 35, the film formation is performed by the microcrystalline silicon film manufacturing apparatus according to the second embodiment. The photoelectric conversion layer 37 is patterned by performing laser scribing from the back side of the translucent insulating substrate 32 so that an opening reaching the surface of the transparent electrode layer 33 is formed.

  Subsequently, a back electrode layer 38 as a second electrode layer is formed. The back electrode layer 38 is subjected to laser scribing from the back side of the translucent insulating substrate 32 so that an opening reaching the surface of the transparent electrode layer 33 together with the photoelectric conversion layer 37 is formed, whereby a plurality of thin film solar cells are formed. A cell (microcrystalline silicon cell) C is formed into a cell.

  As a comparative example, electrical characteristics (voltage) of a thin-film solar cell (microcrystalline silicon cell) C of a module 31 in which a power generation layer (i-type microcrystalline silicon film) is produced using a conventional microcrystalline silicon film manufacturing apparatus. -Current characteristics: IV characteristics) are also shown in FIG. The thin film solar cell C (module 31) of the comparative example is the thin film solar cell of the example, except that a power generation layer (i-type microcrystalline silicon film) was produced using a conventional microcrystalline silicon film manufacturing apparatus. It has the same configuration as the battery cell C (module 31).

  In FIG. 13, a solid line Z indicates a thin film solar cell (microscopic) of a module 31 (example) in which a power generation layer (i-type microcrystalline silicon film) is produced using the microcrystalline silicon film manufacturing apparatus according to the second embodiment. 4 shows the IV characteristics of the crystalline silicon cell) C, and the dotted line W indicates the thin film solar of the module 31 (comparative example) in which a power generation layer (i-type microcrystalline silicon film) is produced using a conventional microcrystalline silicon film manufacturing apparatus. The IV characteristic of the battery cell (microcrystalline silicon cell) C is shown.

  As is apparent from FIG. 13, a thin-film solar cell (microcrystalline silicon cell) C (implementation) in which a power generation layer (i-type microcrystalline silicon film) is produced using the microcrystalline silicon film manufacturing apparatus according to the second embodiment. In the example), the short-circuit current density and the open-circuit voltage are increased.

Table 1 shows the power generation efficiency (%), the short-circuit current density (mA / cm ² ), the open-circuit voltage (V), and the fill factor of the thin-film solar cells (microcrystalline silicon cells) C of Examples and Comparative Examples. .

From the results shown in Table 1, the short-circuit current density (mA / cm ² ) and the open end were obtained by producing a power generation layer (i-type microcrystalline silicon film) using the microcrystalline silicon film manufacturing apparatus according to the second embodiment. As for the voltage (V), all the characteristics are improved by nearly 10%, and as a result, the power generation efficiency is increased by about 1.3%. As described above, the power generation layer (i-type microcrystalline silicon film) having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ manufactured using the apparatus for manufacturing a microcrystalline silicon film according to the second embodiment is a microcrystalline silicon thin film. It turns out that there exists an effect which improves electric power generation efficiency in a solar cell.

As described above, in the microcrystalline silicon film manufacturing apparatus according to the second embodiment, similarly to the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the microcrystalline silicon film manufacturing apparatus according to the first embodiment is formed on the transparent insulating substrate 2. The crystal silicon film has a structure for monitoring and evaluating the crystallization rate I ₅₂₀ / I ₄₈₀ of in-situ Raman spectroscopy measurement. By providing such a configuration, the laser beam 14 was irradiated from the back side of the translucent insulating substrate 2 placed on the substrate stage 1 during film formation, and generated on the back side of the microcrystalline silicon film 7. The Raman scattered light 15 is measured (Raman spectroscopy), and the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 can be monitored through the translucent insulating substrate 2. By using Raman spectroscopy, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 having a film thickness of 100 nm or less can be accurately evaluated even through the translucent insulating substrate 2.

Then, the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 (≦ 100 nm) is monitored, and based on the information of the obtained crystallization rate I ₅₂₀ / I ₄₈₀ , the crystallization rate I ₅₂₀ / I. _The film forming parameters (feed amount of raw material gas and high frequency power applied to the shower head 4) are adjusted by automatic control by feeding back the film forming conditions so that ₄₈₀ becomes a target value. Thereby, it is possible to increase the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial layer of film formation, and without forming an incubation layer, microcrystalline silicon having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction. A film can be formed.

  In the microcrystalline silicon film manufacturing apparatus according to the second embodiment, the monitor window 12 is positioned on the back side of the translucent insulating substrate 2 as in the microcrystalline silicon film manufacturing apparatus according to the first embodiment. Therefore, the automatic control of the feedback of the film forming conditions can be appropriately performed without reducing the accuracy of the automatic control of the feedback of the film forming conditions during the film formation.

  Therefore, according to the apparatus for manufacturing a microcrystalline silicon film according to the second embodiment, a microcrystalline silicon film having a stable film quality with a substantially uniform crystallization rate in the film thickness direction can be formed with a high yield. A microcrystalline silicon film having a substantially uniform crystallization rate in the direction can be formed with high yield.

Further, in the method for manufacturing a microcrystalline silicon film according to the second embodiment, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 formed on the translucent insulating substrate 2 is transmitted in-situ. and Raman spectrometry was monitored from the back side of sexual insulating substrate 2, based on the obtained information of the crystallization ratio _I 520 _{/ I 480,} form a film having a crystallization ratio _I 520 _{/ I 480} is the target value The film forming parameters (feed amount of raw material gas and high frequency power applied to the shower head 4) are adjusted by automatic control by feeding back the conditions. As a result, the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial film formation layer can be increased, and a microcrystalline silicon film having a substantially uniform crystallization rate in the film thickness direction can be formed with good yield without forming an incubation layer. can do.

Embodiment 3 FIG.
FIG. 15 is a schematic diagram illustrating a structure of a microcrystalline silicon film manufacturing apparatus according to the third embodiment. FIG. 15 shows a top view of the substrate stage 1 and the shower head 4. As shown in FIG. 15, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the monitoring points (monitoring points Pa to Pi) for measuring the crystallization rate I ₅₂₀ / I ₄₈₀ when the microcrystalline silicon film is formed. However, it is configured to be provided at nine locations in the in-plane direction of the substrate stage 1. Here, although nine monitoring points are provided, the number of monitoring points is not limited to this.

  In each of the monitoring points Pa to Pi, holes 8 (8a to 8i) are provided inside the upper surface side (side holding the translucent insulating substrate 2) of the substrate stage 1, respectively. Moreover, the monitor window 12 (not shown) and the lens 9 (not shown) corresponding to each hole 8 (8a-8i) are each installed in the inside of the hole 8 (8a-8i). Corresponding lead lines 27a to 27i are connected to the lens 9, respectively.

  The laser light 14 emitted from the Raman laser light source 10 is incident on the lead lines 27 a to 27 i through the branch fiber line 28 via the optical fiber line 11. Then, the laser beam 14 is incident on the lens 9 from the lead lines 27a to 27i, passes through the monitor windows 12 (12a to 12i) provided in the upper part of the holes 8 (8a to 8i), and is transmitted through the transparent insulating substrate 2. The microcrystalline silicon film 7 is irradiated from the back side (lower surface side).

  Here, the branch fiber line 28 is configured to be instantaneously switched and connected to the lead lines 27a to 27i. The lead line 27a is in the hole 8a of the monitoring point Pa, and the lead line 27b is in the hole of the monitoring point Pb. 8b, the lead line 27c is in the hole 8c of the monitoring point Pc, the lead line 27d is in the hole 8d of the monitoring point Pd, the lead line 27e is in the hole 8e of the monitoring point Pe, and the lead line 27f is in the hole 8f of the monitoring point Pf. The lead wire 27g is connected to the hole 8g of the monitoring point Pg, the lead wire 27h is connected to the hole 8h of the monitoring point Ph, and the lead wire 27i is connected to the hole 8i of the monitoring point Pi.

  The Raman scattered light 15 generated by irradiating the microcrystalline silicon film 7 with the laser light 14 is directed in the opposite direction to the laser light 14 from the monitor window 12 (12a-12i) to the lens 9, lead lines 27a-27i, and the optical fiber line 11. The light is received by the spectroscope 13 and a Raman spectrum as shown in FIG. 2 is obtained.

The spectrometer 13 is connected to a silane gas (SiH ₄ ) supply mass flow 16 and a hydrogen gas (H ₂ ) supply mass flow 17 via a controller 18. From the Raman spectrum information at the nine monitoring points Pa to Pi detected by the spectroscope 13, the controller 18 calculates the crystallization ratios I ₅₂₀ / I ₄₈₀ at nine locations in the in-plane direction of the microcrystalline silicon film 7 substantially simultaneously. The controller 18 supplies the silane gas (SiH ₄ ) supply mass flow 16 and the hydrogen gas (H ₂ ) so that the measured value of the crystallization rate I ₅₂₀ / I ₄₈₀ monitored and read by the spectroscope 13 approaches the target value. The mass flow 17 is automatically controlled to feed back the supply amount of the source gas during the film forming process.

That is, as in the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the supply amount of the source gas, which is a film forming parameter, is automatically controlled during film formation. As a result, the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial film formation layer can be increased, and a microcrystalline silicon film having a uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction without forming an incubation layer. Can be formed.

Here, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, as shown in FIG. 15, the silane gas (SiH ₄ ) supply mass flow 16 and the hydrogen gas (H ₂ ) supply mass flow 17 are connected to each monitoring point ( Nine (corresponding to the monitoring points Pa to Pi) are provided (silane gas (SiH ₄ ) supply mass flows 16a to 16i, hydrogen gas (H ₂ ) supply mass flows 17a to 17i). The shower head 4 is divided into nine regions (shower head regions 4a to 4i) corresponding to the respective monitoring points (monitoring points Pa to Pi). The silane gas (SiH ₄ ) supply mass flow 16 (16a to 16i) and the hydrogen gas (H ₂ ) supply mass flow 17 (17a to 17i) are respectively connected through the corresponding gas supply pipes 3 (3a to 3i). Are connected to the corresponding showerhead regions 4a-4i.

Then, the controller 18 uses the silane gas (SiH ₄ ) supply mass flows 16a to 16i and hydrogen gas (hydrogen gas (SiH ₄ ) supply so that the crystallization rate I ₅₂₀ / I ₄₈₀ measured at each monitoring point (monitoring points Pa to Pi) approaches the target value. H ₂ ) It is possible to individually control the supply mass flows 17a to 17i and individually adjust the “gas supply amount” from the shower head regions 4a to 4i to the translucent insulating substrate 2. .

  As shown in FIG. 15, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, nine power supplies 5 (power supplies 5a to 5i) are provided corresponding to each monitoring point (monitoring points Pa to Pi). Are connected to the corresponding shower head regions 4a to 4i through power lines 19 (19a to 19i), respectively.

Then, the controller 18 individually controls the power supplies 5a to 5i independently so that the crystallization ratios I ₅₂₀ / I ₄₈₀ measured at the respective monitoring points (monitoring points Pa to Pi) approach the target value. It is possible to individually adjust the “high-frequency power applied to the shower head regions 4a to 4i”.

As described above, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the monitoring mechanisms of the crystallization ratios I ₅₂₀ / I ₄₈₀ are provided at nine locations on the substrate stage 1 and correspond to each monitoring point. The shower head 4 is divided into a plurality of regions. Then, the “gas supply amount” from the corresponding shower head region and the “high frequency power applied to the shower head region” so that the value of the crystallization rate I ₅₂₀ / I ₄₈₀ measured at each monitoring point approaches the target value. Can be adjusted individually. Thus, a microcrystalline silicon film having a substantially uniform crystallization ratio I ₅₂₀ / I ₄₈₀ in the film thickness direction can be formed with high yield.

FIG. 16 shows the in-plane measurement values of the crystallization rate I ₅₂₀ / I ₄₈₀ of an i-type microcrystalline silicon film formed on a 100 mm square substrate with a film thickness of 2 μm using a conventional microcrystalline silicon film manufacturing apparatus. It is a characteristic view which shows distribution. FIG. 17 shows an in-plane distribution of measured values of the crystallization ratios I ₅₂₀ / I ₄₈₀ of an i-type microcrystalline silicon film manufactured with a film thickness of 2 μm using the microcrystalline silicon film manufacturing apparatus according to the third embodiment. FIG. Here, the crystallization rate I ₅₂₀ / I ₄₈₀ is a Raman value obtained by measuring the in-plane 64 locations (vertical and horizontal 8 × 8 locations) of the i-type microcrystalline silicon film formed on a 100 mm square substrate by Raman spectroscopy. The peak intensity ratio is I ₅₂₀ / I ₄₈₀ .

As shown in FIG. 17, in the i-type microcrystalline silicon film manufactured by the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the crystallization ratio I ₅₂₀ / I ₄₈₀ falls within the range of 4% to 4.3%. Thus, it can be seen that ± 1.5% is obtained as the in-plane distribution of the crystallization rate I ₅₂₀ / I ₄₈₀ . In contrast, in FIG. 16 is a region of low crystallization ratio _I 520 _{/ I 480} is present at the periphery of the substrate stage 1 (translucent insulating substrate 2), the crystallization ratio _I 520 _{/ I 480} The in-plane distribution is ± 7.5%, which is about 5 times inferior to the i-type microcrystalline silicon film formed using the microcrystalline silicon film manufacturing apparatus according to the third embodiment. This is because hydrogen (H ₂ ) is supplied from the shower head to the substrate surface substantially uniformly in the conventional apparatus for producing a microcrystalline silicon film, so that hydrogen (accelerating the crystallization reaction) at the end of the substrate stage ( H) The supply of radicals is insufficient.

However, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the supply amount of hydrogen gas (H ₂ ) to the surface of the translucent insulating substrate 2 can be controlled independently for each region. Thus, hydrogen (H) radicals can be sufficiently supplied also at the end of the substrate stage 1. As a result, the in-plane distribution of the crystallization ratio I ₅₂₀ / I ₄₈₀ can be improved by about 5 times compared to the conventional case.

  FIG. 18 is a characteristic diagram showing an in-plane distribution of power generation efficiency of a thin-film solar cell (microcrystalline silicon cell) in which an i-type microcrystalline silicon film (power generation layer) is manufactured using a conventional microcrystalline silicon film manufacturing apparatus. It is. FIG. 19 shows an in-plane distribution of power generation efficiency of a thin-film solar cell (microcrystalline silicon cell) in which an i-type microcrystalline silicon film (power generation layer) is produced using the microcrystalline silicon film manufacturing apparatus according to the third embodiment. FIG. Here, a total of 64 thin-film solar cells (microcrystalline silicon cells) are produced on a 100 mm square size translucent insulating substrate, and the in-plane distribution of the measurement results of these power generation efficiencies (%) is displayed. . In addition, since the thin film photovoltaic cell (microcrystalline silicon cell) located in an outer periphery is used for the connection of an electrode, the number of the actual measurement cells is 49 pieces.

From FIG. 19, in the 49 thin film solar cells (microcrystalline silicon cells) on the translucent insulating substrate, the power generation efficiency (%) is all within the range of 7% to 7.4%. It can be seen that ± 1.1% is obtained as the distribution. On the other hand, in FIG. 18, the power generation efficiency (%) is high in the central portion of the translucent insulating substrate, and shows an in-plane distribution that gradually decreases toward the periphery, which is the crystallization rate shown in FIG. The deviation (in-plane distribution) of I ₅₂₀ / I ₄₈₀ is reflected. The in-plane distribution of power generation efficiency in FIG. 18 is ± 4.6%, which is approximately four times inferior to the in-plane distribution of the cell according to the third embodiment. That is, by using the microcrystalline silicon film manufacturing apparatus according to the third embodiment to form an i-type microcrystalline silicon film (power generation layer) to produce a thin film solar cell (microcrystalline silicon cell), power generation efficiency The in-plane distribution can be improved about four times compared to the conventional case.

As described above, when the microcrystalline silicon film is formed using the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the in-plane distribution of the crystallization ratios I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film is obtained. Thus, it becomes possible to make adjustment almost uniformly as compared with the conventional case. Then, when an i-type microcrystalline silicon film (power generation layer) is formed using the microcrystalline silicon film manufacturing apparatus according to the third embodiment to produce a thin film solar cell (microcrystalline silicon cell), power generation The in-plane distribution of efficiency can be improved as compared with the conventional case and can be adjusted substantially uniformly. That is, it is possible to obtain a thin-film solar battery cell (microcrystalline silicon cell) that achieves higher power generation efficiency and better in-plane distribution as compared with the conventional case.

As described above, in the microcrystalline silicon film manufacturing apparatus according to the third embodiment, similarly to the microcrystalline silicon film manufacturing apparatus according to the first embodiment, the microcrystalline silicon film manufacturing apparatus according to the first embodiment is formed on the translucent insulating substrate 2. The crystal silicon film has a structure for monitoring and evaluating the crystallization rate I ₅₂₀ / I ₄₈₀ of in-situ Raman spectroscopy measurement. By providing such a configuration, the laser beam 14 was irradiated from the back side of the translucent insulating substrate 2 placed on the substrate stage 1 during film formation, and generated on the back side of the microcrystalline silicon film 7. The Raman scattered light 15 is measured (Raman spectroscopy), and the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 can be monitored through the translucent insulating substrate 2. By using Raman spectroscopy, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 having a film thickness of 100 nm or less can be accurately evaluated even through the translucent insulating substrate 2.

Then, the crystallization rate I ₅₂₀ / I ₄₈₀ of the growing microcrystalline silicon film 7 (≦ 100 nm) is monitored, and based on the information of the obtained crystallization rate I ₅₂₀ / I ₄₈₀ , the crystallization rate I ₅₂₀ / I. _The film forming parameters (feed amount of raw material gas and high frequency power applied to the shower head 4) are adjusted by automatic control by feeding back the film forming conditions so that ₄₈₀ becomes a target value. Thereby, it is possible to increase the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial layer of film formation, and without forming an incubation layer, microcrystalline silicon having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction. A film can be formed.

Furthermore, in the apparatus for manufacturing a microcrystalline silicon film according to the third embodiment, the monitoring mechanism of the crystallization rate I ₅₂₀ / I ₄₈₀ is provided at a plurality of locations on the substrate stage 1, and the crystallization measured at each monitoring point is performed. The “gas supply amount” from the corresponding shower head region and the “high frequency power applied to the shower head region” are individually adjusted so that the value of the rate I ₅₂₀ / I ₄₈₀ approaches the target value. Thus, a microcrystalline silicon film having a substantially uniform crystallization ratio I ₅₂₀ / I ₄₈₀ in the film thickness direction can be formed with high yield.

In the microcrystalline silicon film manufacturing apparatus according to the third embodiment, the monitor window 12 is positioned on the back side of the translucent insulating substrate 2 as in the microcrystalline silicon film manufacturing apparatus according to the first embodiment. Therefore, automatic control of film forming condition feedback can be appropriately performed without reducing the accuracy of automatic film forming condition feedback during film formation, and the crystallization ratio I ₅₂₀ / A microcrystalline silicon film with substantially uniform I ₄₈₀ can be formed with high yield.

  Therefore, according to the microcrystalline silicon film manufacturing apparatus according to the third embodiment, a microcrystalline silicon film having a stable film quality with a substantially uniform crystallization rate in the film thickness direction while maintaining a good in-plane distribution. It can be formed with high yield.

Further, in the method for manufacturing a microcrystalline silicon film according to the third embodiment, the crystallization rate I ₅₂₀ / I ₄₈₀ of the microcrystalline silicon film 7 formed on the translucent insulating substrate 2 is transmitted in-situ. and Raman spectrometry was monitored from the back side of sexual insulating substrate 2, based on the obtained information of the crystallization ratio _I 520 _{/ I 480,} form a film having a crystallization ratio _I 520 _{/ I 480} is the target value The film forming parameters (feed amount of raw material gas and high frequency power applied to the shower head 4) are adjusted by automatic control by feeding back the conditions. Thereby, it is possible to increase the crystallization rate I ₅₂₀ / I ₄₈₀ of the initial layer of film formation, and without forming an incubation layer, microcrystalline silicon having a substantially uniform crystallization rate I ₅₂₀ / I ₄₈₀ in the film thickness direction. A film can be formed with high yield.

Furthermore, in the method for manufacturing a microcrystalline silicon film according to the third embodiment, the crystallization ratios I ₅₂₀ / I ₄₈₀ are monitored at a plurality of locations (monitoring points) of the microcrystalline silicon film 7 and measured at each monitoring point. The “gas supply amount” from the corresponding shower head region and the “high frequency power applied to the shower head region” are individually adjusted so that the value of the crystallization rate I ₅₂₀ / I ₄₈₀ approaches the target value. Accordingly, a microcrystalline silicon film with a more uniform crystallization ratio I ₅₂₀ / I ₄₈₀ in the film thickness direction can be formed with a high yield while maintaining a good in-plane distribution.

  Moreover, by using the apparatus for producing a microcrystalline silicon film according to the above-described embodiment, it is good even on a large area glass substrate (1.1 × 1.4 meters) generally used in mass production of thin film solar cells. Power generation efficiency is expected to be realized with a good in-plane distribution.

  In the above description, a single cell thin film solar cell having only one photoelectric conversion layer has been described as an example. However, the present invention can also be applied to a tandem thin film solar cell in which a plurality of photoelectric conversion layers are stacked. In this case, the effect of the present invention becomes more remarkable as the number of stacked photoelectric conversion layers (power generation layers) increases. In the above description, the film forming parameters are automatically controlled based on the crystallization rate of the microcrystalline silicon film 7. However, the film forming parameters can be manually controlled according to the situation.

  As described above, the microcrystalline silicon film manufacturing apparatus and the microcrystalline silicon film manufacturing method according to the present invention are useful for manufacturing a microcrystalline silicon film having a stable film quality in the film thickness direction. Suitable for manufacturing thin film solar cells.

DESCRIPTION OF SYMBOLS 1 Substrate stage 2 Translucent insulated substrate 3 Gas supply piping 4 Shower head 4a-4i Shower head area 5 Power source 5a-5i Power source 6 Plasma 7 Microcrystalline silicon film 8 Hole 8a-8i Hole 9 Lens 10 Raman laser light source 11 Optical fiber line 12 monitor window 13 spectroscope 14 laser beam 15 Raman scattered light 16 silane gas (SiH ₄₎ for supplying a mass flow 16a~16i silane gas (SiH ₄₎ for supplying a mass flow 17 supplied mass flow 17a~17i hydrogen gas _{(H 2)} for supplying a mass flow 18 Controller 19 Power supply line 19a to 19i Power supply line 21 Glass substrate 22 Amorphous silicon layer 23 Microcrystalline silicon film 24 Microcrystalline silicon film 27a to 27i Lead line 28 Branch fiber line 31 Module 32 Translucent insulating substrate 33 Transparent Bright electrode layer 34 p-type microcrystalline silicon film (μc-Si film)
35 i-type microcrystalline silicon film (μc-Si film)
36 n-type microcrystalline silicon film (μc-Si film)
37 Photoelectric conversion layer 38 Back electrode layer Pa to Pi Monitoring point R Film forming chamber

Claims (13)

A substrate to be processed having translucency is held on a substrate stage, and a plasma of the source gas is generated in a state where the source gas is supplied toward a film forming surface of the substrate to be processed, and the source gas is generated by the plasma. A film forming chamber for forming a microcrystalline silicon film by decomposing and depositing on the film surface;
Measuring means for measuring the crystallization rate of the microcrystalline silicon film through the substrate stage and the substrate to be processed by Raman spectroscopy from the opposite side of the substrate surface to be processed in the substrate to be processed;
An apparatus for producing a microcrystalline silicon film, comprising: A window for Raman spectroscopy evaluation for monitoring the crystallization rate of the microcrystalline silicon film provided on the substrate side of the substrate stage;
A Raman laser light source for irradiating the microcrystalline silicon film with the laser beam for Raman spectroscopic evaluation through the window and the substrate to be processed;
A spectroscope for measuring Raman scattered light generated by irradiating the microcrystalline silicon film with the laser light through the substrate to be processed and the window;
An arithmetic means for calculating a crystallization rate of the microcrystalline silicon film based on the Raman scattered light measured by the spectroscope,
The apparatus for producing a microcrystalline silicon film according to claim 1, comprising: A supply amount control means for automatically controlling the supply amount of the source gas based on the crystallization rate of the microcrystalline silicon film obtained by the computing means during the formation of the microcrystalline silicon film;
The apparatus for producing a microcrystalline silicon film according to claim 2. The window portion is provided at a plurality of measurement locations of the substrate stage, and the crystallization rate is measured at a plurality of locations of the microcrystalline silicon film,
The apparatus for producing a microcrystalline silicon film according to claim 3. The supply amount control means automatically controls the supply amount of the source gas independently for each region corresponding to the measurement location;
The apparatus for producing a microcrystalline silicon film according to claim 4. Applied power control means for automatically controlling applied power for generating the plasma based on the crystallization rate of the microcrystalline silicon film obtained by the computing means during the formation of the microcrystalline silicon film. Preparing,
The apparatus for producing a microcrystalline silicon film according to claim 2. The window portion is provided at a plurality of measurement locations of the substrate stage, and the crystallization rate is measured at a plurality of locations of the microcrystalline silicon film,
The apparatus for producing a microcrystalline silicon film according to claim 6. The applied power control means automatically controls the applied power independently for each region corresponding to the measurement location;
The apparatus for producing a microcrystalline silicon film according to claim 7. A plasma of the source gas is generated in a state where the source gas is supplied toward the film-forming surface of the substrate to be processed having translucency, and the source gas is decomposed by the plasma and deposited on the film-forming surface. A first step of forming a microcrystalline silicon film on the substrate to be processed;
A second step of measuring the crystallization rate of the microcrystalline silicon film through the substrate stage and the substrate to be processed by Raman spectroscopy from the opposite side of the substrate surface to be processed in the substrate to be processed;
A method for producing a microcrystalline silicon film, comprising: Automatically controlling the supply amount of the source gas based on the crystallization rate of the microcrystalline silicon film during the formation of the microcrystalline silicon film;
The method for producing a microcrystalline silicon film according to claim 9. Measuring the crystallization rate in a plurality of locations of the microcrystalline silicon film, and automatically controlling the supply amount of the source gas independently for each region corresponding to the measurement location;
The method for producing a microcrystalline silicon film according to claim 10. Automatically controlling applied power for generating the plasma based on the crystallization rate of the microcrystalline silicon film during the formation of the microcrystalline silicon film;
The method for producing a microcrystalline silicon film according to claim 9. Measuring the crystallization rate in a plurality of locations of the microcrystalline silicon film, and automatically controlling the applied power independently for each region corresponding to the measurement location;
The method for producing a microcrystalline silicon film according to claim 12.