Substrate controllable step morphology pre-processing method of silicon carbide pyrolysis prepared graphene

Abstract

The present invention discloses a substrate controllable step morphology pre-processing method applied to the silicon carbide pyrolysis prepared graphene. The method comprises the following steps of (1) placing a silicon carbide substrate on a pedestal in a chemical vapor deposition (CVD) device; (2) setting the pressure in a reaction chamber and the hydrogen flow, and warming to a beginning etching temperature under the hydrogen atmosphere; (3) keeping the pressure and the H2 flow to be constant, letting in the small flow carbon source auxiliary etching while continuously warming to a final etching temperature; (4) after warming to the final etching temperature, keeping the pressure, the temperature and the H2 flow to be constant, and improving the carbon source flow auxiliary etching slowly in a linear slowly varying manner; (5) closing a valve through which a carbon source gets in the reaction chamber, carrying out the pure H2 etching; (6) letting in the silane auxiliary H2 etchingtowards the reaction chamber; (7) cooling to a room temperature under the hydrogen atmosphere, and taking out a pre-processed silicon carbide substrate. The advantages of the present invention are that: a controllable technology window of the pure hydrogen etching is expanded, at the same time, the problem that due to the pure hydrogen etching, the steps on the surface of the substrate are difficult to control is solved. According to the present invention, a sub-damage layer on the surface of the substrate is removed effectively, the controllable, flat and straight steps having no defects alsocan be formed on the surface of the silicon carbide substrate, the dissociation speeds on the steps are consistent, and the supply speeds of the carbon atoms on the step surfaces are same, the growngraphene can be more uniform. The pre-processing method has a higher popularization 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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