A transistor with self-aligned feedback gate and its preparation method

Abstract

The invention discloses a thin film transistor with a self-aligned feedback gate structure and a preparation method thereof. According to the method, a pseudo side wall layer is prepared after a conventional gate structure, patterning of a feedback gate dielectric layer and a feedback gate metal layer is achieved by using the pseudo side wall layer as a self-alignment mask, finally the pseudo sidewall layer is cleaned away, and preparation of a source-drain metal electrode, physical connection and electrical connection of the source-drain electrode and the feedback gate metal electrode are conducted. A thin film transistor with a feedback gate structure is formed in the process. According to the method, a self-alignment feedback gate process with more accurate size is provided, and meanwhile, flexible adjustment of materials of the drain end metal electrode and the feedback gate metal electrode, and thicknesses and types of the main gate medium and the feedback gate medium is achieved.

Description

technical field [0001] The invention relates to a semiconductor thin film transistor and a preparation method thereof, in particular to a transistor with a self-aligned feedback gate and a preparation method thereof. Background technique [0002] As semiconductor technology continues to shrink down to technology nodes below 3nm, silicon-based integrated circuits are very likely to reach the limits of silicon materials and physical quantum mechanics. With the continued development of electronics, there is an urgent need to find new materials with more potential and advantages to replace silicon materials and break through the limit of Moore's Law. Carbon nanotubes (CNTs) have ultra-high carrier mobility, mean free path, and nanometer-scale diameter, and can be used to construct nanometer field-effect transistors with faster speed, lower power consumption, and smaller size, so carbon Nanotube (CNTs) electronics is considered to be one of the future information technologies mo...

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Problems solved by technology

[0004] The current semi-self-aligned feedback gate process still has many shortcomings. For example, the length of the feedback gate is still determined by the overlay accuracy in the photolithography process. Excessive deviation of the process will directly limit the performance and threshold of the transistor. At the same time, the existing The drain contact metal electrode and the feedback gate metal electrode of the self-aligned feedback gate structure are made of the same material, which cannot flexibly adjust the work function of the feedback gate metal and the work function of the drain contact material. In addition, there are self-aligned feedback The main gate dielectric layer and the feedback gate dielectric layer of the gate structure are formed in a one-step process, and the thickness and type of the main gate dielectric and the feedback gate dielectric cannot be flexibly adjusted, so the interface and threshold are also difficult to adjust

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