Method and reactor for preparing films and devices under high nitrogen chemical potential

Abstract

Nitride semiconductor films, such as for use in solid state light emitting devices and electronic devices, are fabricated in an environment of relatively high nitrogen potential such that nitrogen vacancies in the growing film are reduced. A reactor design, and method for its use, provide high nitrogen precursor partial pressure, precracking of the precursor using a catalytic metal surface, prepyrolyzing the precursor, using catalytically-cracked molecular nitrogen as a nitrogen precursor, and / or exposing the surface to an ambient which is extremely rich in active nitrogen species. Improved efficiency for light emitting devices, particularly in the blue and green wavelengths and improve transport properties in nitride electronic devices, i.e., improved performance from nitride-based devices such as InGaAlN laser diodes, transistors, and light emitting diodes is thereby provided.

Description

technical field [0001] The present invention relates to semiconductor devices and methods of making the same; and more particularly, to epitaxial nitride semiconductor thin films, heterostructures and devices, and methods of making them under conditions of high nitrogen chemical potential. Background technique [0002] Nitride semiconductor light-emitting diodes (LEDs), laser diodes (LDs), and electronic devices are typically formed by metal-organic chemical vapor deposition (MOCVD) epitaxial growth. For aluminum-gallium-indium-nitride (AlGaInN) quantum well (QW) LEDs and LDs, the AlGaInN quantum well active region and pn structure form a key part of the device. An ideal crystalline film for such nitride devices should be free of neither extended defects (such as dislocations or phase boundaries resulting from lattice mismatch) nor point defects (such as impurities, vacancies, interstitials, etc.). It is these deficiencies that prevent light-emitting devices from achieving ...

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Problems solved by technology

This explanation is consistent with the relatively poor performance of green (high indium content) emitters

However, we also note that this is contrary to many conventional explanations, including the formation of high-voltage electric fields, alloy inhomogeneities, and possible strain-related structural defects

[0014] Although the mechanism by which the improved optoelectronic quality is obtained is not fully understood, these examples suggest that film growth may be beneficial in the presence of high nitrogen partial pressures

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