A kind of deposition method of polysilicon thin film

Abstract

The invention provides a deposition method for polycrystalline silicon films. According to the deposition method for polycrystalline silicon films, a vertical tube furnace is adopted, and silane is adopted as the reactant gas for carrying out deposition of polycrystalline silicon films; and during deposition, the flows of the nozzles at the very bottom are basically the same as those of the nozzles on the most top, and are larger than those of the nozzles in the middle, and the gas flows of the nozzles in the middle increase successively from bottom to top. Because the reactant gas flows from bottom to top and is successively consumed during flow, and the gas flows of the nozzles in the middle increase successively to make up for the gas consumed in the flowing process, the uniformity between wafers is improved. Furthermore, the gas flow at the topmost end is increased, the partial pressure caused by the hydrogen generated during the reaction is lowered, and the uniformity of the polycrystalline silicon films in the wafers on the top is further improved. Therefore, the uniformity between wafers and the uniformity of the polycrystalline silicon films in the wafers are improved comprehensively.

Description

technical field [0001] The invention relates to the field of semiconductor devices and their manufacture, in particular to a method for depositing polysilicon thin films. Background technique [0002] Polysilicon is an important material in semiconductor devices and their manufacture, and polysilicon thin films are important structures in semiconductor devices. At present, vertical tube furnaces are mainly used for silane (SiH 4 ) is the reaction gas for the deposition of polysilicon film. [0003] refer to figure 1 As shown, the vertical tube furnace is provided with many crystal boats from top to bottom, and each crystal boat is used to place wafers to be deposited with polysilicon. The lower nozzle has the largest gas flow rate, and the gas flow through the other nozzles is used as compensation for the consumed gas, so that the uniformity of the film layer between the wafers can be improved. However, in the actual manufacturing process, there is a problem of poor film...

AI Technical Summary

Problems solved by technology

However, in the actual manufacturing process, there is a problem of poor film thickness uniformity in the wafer at the top of the tube furnace, especially when the film thickness of deposited polysilicon is about 1500 Angstroms, the uniformity is the worst

The uneven thickness of the polysilicon film will have a certain impact on the stability, reliability and service life of the device, and at the same time bring certain difficulties to the control of the process, and may cause leakage and cause the device to fail to work

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