Substrate Controlled Step Morphology Pretreatment Method for Graphene Prepared by Pyrolysis of Silicon Carbide

Abstract

The invention discloses a substrate controllable step morphology pretreatment method applied to silicon carbide pyrolysis to prepare graphene, comprising the following steps: (1) placing a silicon carbide substrate on a base in a chemical vapor deposition CVD device above; (2) set the reaction chamber pressure and hydrogen flow rate, and raise the temperature to the etching start temperature under the hydrogen atmosphere; (3) maintain the pressure and H 2 The flow rate remains the same, and continue to heat up to the final etching temperature while feeding a small flow of carbon source to assist etching; (4) After heating up to the final etching temperature, keep the pressure, temperature and H 2 The flow rate is constant, and the carbon source flow rate is slowly increased in a linear and gradual manner to assist etching; (5) Close the valve of the carbon source into the reaction chamber, and the pure H 2 Etching; (6) Introducing silane into the reaction chamber to assist H 2 Etching; (7) The hydrogen atmosphere is cooled to room temperature, and the pretreated silicon carbide substrate is taken out. Advantages: expand the controllable process window of pure hydrogen etching, and at the same time solve the problem that the steps on the substrate surface caused by pure hydrogen etching are difficult to control. It can not only effectively remove the sub-damaged layer on the surface of the substrate, but also form a controllable flat and defect-free step on the surface of the silicon carbide substrate, with the same dissociation speed on it, and the same supply speed of carbon atoms on the mesa, which can make the grown graphite Alkenes are more uniform. It has high promotional value.

Description

technical field [0001] The invention specifically relates to a substrate controllable step morphology pretreatment method applied to the pyrolysis of silicon carbide to prepare graphene. The invention belongs to the technical field of semiconductor epitaxy materials. Background technique [0002] Graphene film has a perfect two-dimensional crystal structure, endowing it with many excellent properties, such as: a two-dimensional planar structure composed of a single atomic layer, larger than 200,000 cm at room temperature 2 / V·s intrinsic electron mobility (140 times that of silicon, and higher than that of carbon nanotubes); mean free path of micron-sized electrons; current density two orders of magnitude higher than that of copper (108 A / cm 2 ); excellent thermal conductivity [~5000 W / (m K)] (5 times that of diamond, and higher than that of carbon nanotubes). Obviously, if the application potential of these intrinsic properties of graphene in the field of radio frequency...

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Problems solved by technology

[0005] The present invention proposes a substrate controllable step morphology pretreatment method applied to the pyrolysis of silicon carbide to prepare graphene. Hydrogen etching, expanding the controllable process window of pure hydrogen etching, and at the same time solving the problem that the steps on the substrate surface caused by pure hydrogen etching are difficult to control

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