Method for inducing amorphous silicon film with tin to be crystallized into polycrystalline silicon film

Abstract

The invention relates to a method for preparing a polycrystalline silicon thin film, in particular to a method for inducing an amorphous silicon thin film with tin to be crystallized into a polycrystalline silicon thin film at a low temperature. according to the main technical scheme of the invention, the method comprises the following steps of: 1, carrying out ultrasonic cleaning on a glass substrate by using acetone and deionized water respectively to clean the glass substrate; 2, growing a layer of amorphous silicon (a-Si:H) thin film on the glass substrate by using a plasma enhanced chemical vapor deposition method (PECVD), wherein the temperature of the substrate is about 200 DEG C, and the thickness of the thin film is 200nm-300nm during deposition; 3, growing a layer of metal tin (Sn) thin film with the thickness of 10nm-20nm on the amorphous silicon thin film by using a physical vapor deposition method so as to obtain a substrate / (a-Si:H) / Sn structure; 4, arranging the substrate / (a-Si:H) / Sn in a heat treatment furnace in a laminated manner, and carrying out heat treatment for more than 1 hour at the temperature of 450 DEG C, then cooling naturally, where nitrogen (N2) is introduced and used as a protection gas during the whole annealing process; and 5, removing the remained metal tin on the surface with concentrated hydrochloric acid with the concentration of 37.5% to finally obtain the polycrystalline silicon thin film which is crystallized under the induction of tin, wherein the particle size is about 70-200nm. The method is applicable to the fields of thin-film field effect transistors and solar cells.

Description

technical field [0001] The invention relates to a method for preparing a polysilicon thin film, specifically a method for inducing the crystallization of an amorphous silicon thin film into a polysilicon thin film by using metal tin at low temperature. Background technique [0002] Compared with the carrier mobility of amorphous silicon film (0.3-1.0cm 2 / (V·s)) compared with polysilicon thin film carrier mobility is 8 to 9 times higher, and thus widely used in flat panel displays, image sensors and solar cells. [0003] In the past few years, many technical methods for preparing polysilicon on glass substrates have been proposed, such as rapid thermal annealing (RTA), excimer laser crystallization (ELA), solid phase crystallization (SPC) and metal-induced crystallization. method (MIC), etc. [0004] The rapid annealing (RTA) process consists of three stages: heating stage, stabilization stage and cooling stage. When the power of the annealing furnace is turned on, the te...

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Problems solved by technology

[0007] The crystallization temperature of (SPC) is too high, and it takes more than 20 hours to crystallize amorphous silicon into polycrystalline silicon at a temperature above 600 ° C. Therefore, it is difficult to be applied on cheap glass substrates. The base material is quartz or single crystal silicon.

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