Thin film transistor and its manufacturing method

Abstract

The invention provides a thin film transistor and a manufacturing method thereof. The thin film transistor comprises a substrate, a polycrystalline silicon layer formed on the substrate, a gate electrode insulation layer formed on the polycrystalline silicon layer and a grid electrode layer formed on the gate electrode insulation layer. A channel region, a source electrode region and a drain electrode region are formed on the polycrystalline silicon layer; the gate electrode insulation layer comprises a first gate electrode insulation layer region, a second gate electrode insulation layer region and a third gate electrode insulation layer region, the thickness of the second gate electrode insulation layer region is smaller than the thickness of the first gate electrode insulation layer region and the third gate electrode insulation layer region, and the grid electrode layer covers the second gate electrode insulation layer region and partially covers the first gate electrode insulation layer region and the third gate electrode insulation layer region. The thin film transistor adopts the gate electrode insulation layers of different thicknesses to reduce the electric field of a contact portion between the channel region and the source electrode region or the drain electrode region, and therefore the purpose of reducing a leak current during closing is achieved. Compared with a thin film transistor adopting an LDD structure, two times of the ion implantation process is not needed when the thin film transistor is manufactured, and therefore manufacturing procedures are simplified and the cost is lowered.

Description

technical field [0001] The invention relates to the field of semiconductor device manufacturing, in particular to a thin film transistor and a manufacturing method thereof. Background technique [0002] Poly-Si thin film transistor (Poly-Si thin film transistor) has been widely used in active matrix display (active matrix display), such as active matrix organic display (AMOLED, Active Matrix Organic Light Emitting Diode), active matrix liquid crystal display (AMLCD , Active Matrix liquidcrystal display), and SRAM. Compared with amorphous silicon thin film transistors, since the crystal lattice of polycrystalline silicon thin film transistors is neatly arranged, it is conducive to the transmission of internal electrons, and the electron mobility (mobility) is faster. In other words, electrons experience less resistance inside them, resulting in serious leakage current problems in the off state, causing the display device to lose charge, or consuming the backup power of the S...

AI Technical Summary

Problems solved by technology

[0005] However, the manufacturing process of the thin film transistor 100 requires two ion implantation processes, and the manufacturing process is relatively complicated.

high manufacturing cost

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