Method for depositing semi-conductor film on substrate by using close-space sublimation technology and device thereof

Abstract

The invention relates to a method for depositing semi-conductor film on a substrate by using close-space sublimation technology, comprising: 1. filling semi-conductor material into a crucible, namely using carrier gas to carry the semi-conductor material to reach into the crucible placed in the film vacuum depositing chamber through a passage; and 2. heating the crucible to heat the semi-conductor material for sublimation to be led into gas phase and deposited on the substrate. The invention has the beneficial effects that: by using carrier gas to carry the semi-conductor material to reach into the crucible placed in the film vacuum depositing chamber through a passage, the semi-conductor material is continuously or at intervals supplied for the film vacuum depositing device directly without opening the film vacuum depositing chamber, and the semi-conductor material carried by the carrier gas can be evenly distributed on the bottom of the crucible by a feeding distributor, thus resolving the problems of the prior art that the enlarged distance between the glass substrate and the raw material caused by reduced capacity of the semi-conductor material in the crucible as the semiconductor material deposits on the glass substrate and forms film, and effectively controlling the uniformity of the film obtained on the same substrate.

Description

technical field [0001] The invention relates to a technology for depositing a semiconductor thin film, in particular to a method and a device for depositing and forming a semiconductor thin film on a substrate by means of near-space sublimation technology. Background of the invention [0002] At present, in the field of cadmium sulfide / cadmium telluride solar cell manufacturing, a method of sublimation deposition in close space to obtain high-quality cadmium telluride is attracting people's attention. The cadmium sulfide / cadmium telluride solar cell obtained by this method is The conversion rate is as high as 16.8%, which is currently the highest in the world (see X. Wu et al., 17th European Photovoltaic Solar Energy Conversion Conference, Munich, Germany, 22-26 Oct. 2001, II, 995-1000). The near-space sublimation process is one of the vapor deposition methods. The material forming the cadmium telluride film (hereinafter referred to as the raw material) is placed in a crucib...

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Problems solved by technology

However, in the past, the general traditional method was to directly fill the raw material cadmium telluride into the crucible at room temperature in advance, and then form a cadmium telluride film by sublimation deposition in close space. When a thin film is deposited on the bottom, the capacity of the cadmium telluride in the crucible will decrease, resulting in an increase in the distance between the glass substrate and the raw material. changes happened

[0003] According to the description of U.S. Patent No. 4207119, No. 6444043 and No. 7220321, in the near-space sublimation process they adopt, firstly, raw materials are added to the crucible before deposition, and the amount added is the maximum capacity that the crucible can bear. In order to supplement The raw materials consumed in the thin film deposition need to be repeatedly added to the crucible. However, there are safety hazards in this operation, because the heated container contains toxic gases, and the vacuum chamber is repeatedly opened to add raw materials during the deposition process. Toxic gas is emitted, so the equipment must be cooled before the raw materials can be filled. However, in this way, in order to fill the crucible with raw materials, the deposition process of the cadmium telluride film on the glass substrate must be interrupted. According to the US No. 7220321 patent records, in actual operation, because only a small amount of cadmium telluride is needed to form a cadmium telluride film, so filling up a crucible is enough to provide a few days of raw material for cadmium telluride deposition. The deposition of cadmium telluride film on the glass substrate, the amount of cadmium telluride remaining in the crucible also decreases with time, and the distance between the glass substrate and the raw material increases, resulting in the morphology and photoelectricity of the polycrystalline cadmium telluride film. performance changes

With the repeated deposition of CdTe thin films, the reproducibility of film thickness and quality gradually decreased. Therefore, when using large-area substrates, due to the repeated use of raw materials in the same crucible for a long time, the results obtained on the same substrate The uniformity of the film cannot be controlled. In addition, the microstructure and morphology of the cadmium telluride particles left in the crucible will also change with the deposition time, which further increases the uncertainty of film uniformity and quality. sex

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