Nitride semiconductor devices and method of their manufacture

Abstract

Affords a manufacturing method enabling nitride-based semiconductor devices containing epitaxial films excelling in flatness and crystallinity to be easily produced, and makes available nitride-based semiconductor devices manufactured by the method. Method of manufacturing nitride semiconductor devices that are formed onto a semiconductor substrate being a compound containing a Group IIIA element for forming compounds with nitrogen, and nitrogen, including steps of heating the semiconductor substrate (1) to a film-deposition temperature, supplying to the substrate a film-deposition gas containing a source gas for the Group IIIA element and a nitrogen source gas, and epitaxially growing onto the semiconductor substrate a thin film (2) of a compound containing the Group IIIA element and nitrogen, and being furnished with a step, in advance of the epitaxial growth step, of heating the semiconductor substrate to a pretreating temperature less than the film-deposition temperature, to clean the surface of the semiconductor substrate.

Description

TECHNICAL FIELD [0001] The present invention relates to nitride semiconductor devices such as light-emitting devices, and to methods of their manufacture; more specifically, the present invention relates to high-quality nitride semiconductor devices excelling in flatness and manufacturable at high yields, and to methods of manufacturing such devices. BACKGROUND ART [0002] In the manufacture of light-emitting and other semiconductor devices, when vapor-phase epitaxial film growth is carried out with a nitride-based single crystal as a substrate, the substrate is annealed with the object of ridding the substrate of contaminants (organic matter, moisture) adhering to it, and defects (scratches, strain, etc.). Inasmuch as this heating process is performed prior to the epitaxial film growth, the process is called “pretreating,”“preheating,”“cleaning,”“purification,” or simply “annealing.”[0003] To date—and this is not limited to nitride semiconductors—the substrate heating temperature in...

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Benefits of technology

[0023] In instances in which hexagonal hillocks on the epitaxial film have formed because the flatness of the semiconductor substrate is unsatisfactory, the hexagonal hillocks are observed to be peaks and valleys of 50 nm to 150 nm height at a pitch of 100 μm to 150 μm. Having the RMS rough

Problems solved by technology

In the case of nitride-based semiconductors, nevertheless, heating the nitride substrate for semiconductor device fabrication to at or above the temperature to which it is heated during film deposition provokes the breaking away of nitrogen from the substrate surface or the decomposition of ammonia (NH3), which renders necessary considerable labor for optimizing the gas-supply parameters—in which there are immense options.

As an extreme example, carrying out pretrea

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