Polycrystalline silicon thin film transistor device and method of fabricating the same

• Main Authors: Lin Shih-Liang, Chen Chia-Kai, Wang Pei-Yun, Jiang Cheng-Wei, Hsiao Hsiang-Yun, Hsu Ting-Yu, Huang Ya-Qin
• Format: Patent
• Language: English
• Published: 13.02.2018
• Subjects: BASIC ELECTRIC ELEMENTS; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; SEMICONDUCTOR DEVICES; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

A method of fabricating a polycrystalline silicon thin film transistor device includes the following steps. A substrate is provided, and a buffer layer having dopants is formed on the substrate. An amorphous silicon layer is formed on the buffer layer having the dopants. A thermal process is performed to convert the amorphous silicon layer into a polycrystalline silicon layer by means of polycrystalization, and to simultaneously out-diffuse a portion of the dopants in the buffer layer into the polycrystalline silicon layer for adjusting a threshold voltage. The polycrystalline silicon layer is patterned to form an active layer. A gate insulating layer is formed on the active layer. A gate electrode is formed on the gate insulating layer. A source doped region and a drain doped region are formed in the active layer.