Low temperature polycrystalline silicon film transistor and manufacturing method thereof

Abstract

The invention discloses a lower temperature polycrystalline silicon film transistor and a manufacturing method thereof. The method comprises the following steps: manufacturing a buffer layer on a substrate; manufacturing an amorphous silicon layer on the buffer layer; covering a metal induced layer on the amorphous silicon layer, and performing metal induced crystallization, so as to convert amorphous silicon layer into a polycrystalline silicon layer; schematizing the polycrystalline silicon layer to form a channel region and a source drain region; etching the surface layer, on which metallics remain due to metal induced crystallization, of the channel region; successively forming a gate-insulation layer, a gate, a layer insulation layer and a source drain electrode on the source drain region and the etched channel region. The polycrystalline silicon film transistor and the manufacturing method thereof, disclosed by the invention, realize the individual control of the density of the metallics on the channel region and the source drain region, so that not only is the density of the metallics on the channel region lower, but also the leaked current is reduced; the density of the metallics on the source drain region is higher, the metallics can be used as adulterants so as to reduce the technology of doping again, and besides, contact resistance is decreased; finally, the influence of the metallics remained in an active region on the performance of devices is eliminated.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a low-temperature polysilicon thin film transistor and a manufacturing method thereof. Background technique [0002] Polysilicon material (poly-silicon, p-Si) has higher mobility compared with amorphous silicon material (a-Si). Therefore, using polysilicon to prepare thin film transistors can obtain devices with faster response. Generally speaking, a thin film transistor has at least a gate, a source, a drain, and an active layer. The conductivity of the active layer can be changed by controlling the voltage of the gate, so that a gap is formed between the source and the drain. In addition, an ohmic contact layer with N-type doping or P-type doping is usually formed on the active layer to reduce the contact between the active layer and the source, or The contact resistance between the channel layer and the drain. [0003] In the prior art, a layer of metal di...

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Problems solved by technology

[0003] In the prior art, a layer of metal diffusion barrier layer, such as silicon dioxide, is usually deposited after the deposition of amorphous silicon, and then a layer of metal induction layer is sputtered to realize crystallization and control the concentration of metal particles reaching the surface of polysilicon. The disadvantage is that although the concentration of metal particles reaching the surface of polysilicon can be controlled, it cannot be controlled in different regions

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