Arizona State University

Soitec

Ilsu Han

Chantal Arena

Subhash Mahajan

Ronald Thomas Bertram, Jr

Ed Lindow

Christiaan J Werkhoven

Ranjan Datta

Rahul Ajay Trivedi

Methods of depositing III-nitride semiconductor materials on substrates include depositing a layer of III-nitride semi-conductor material on a surface of a substrate in a nucleation HVPE process stage to form a nucleation layer having a microstructure comprising at least some amorphous III-nitride semiconductor material. The nucleation layer may be annealed to form crystalline islands of epitaxial nucleation material on the surface of the substrate. The islands of epitaxial nucleation material may be grown and coalesced in a coalescence HVPE process stage to form a nucleation template layer of the epitaxial nucleation material. The nucleation template layer may at least substantially cover the surface of the substrate. Additional III-nitride semiconductor material may be deposited over the nucleation template layer of the epitaxial nucleation material in an additional HVPE process stage. Final and intermediate structures comprising III-nitride semiconductor material are formed by such methods.

Template layers for heteroepitaxial deposition of III-nitride semiconductor materials using HVPE processes

This invention provides methods for fabricating substantially continuous layers of a group III nitride semiconductor material having low defect densities and optionally having a selected crystal polarity. The methods include epitaxial growth nucleating and/or seeding on the upper portions of a plurality of pillars/islands of a group III nitride material that are irregularly arranged on a template structure. The upper portions of the islands have low defect densities and optionally have a selected crystal polarity. The invention also includes template structures having a substantially continuous layer of a masking material through which emerge upper portions of the pillars/islands. The invention also includes such template structures. The invention can be applied to a wide range of semiconductor materials, both elemental semiconductors, e.g., combinations of Si (silicon) with strained Si (sSi) and/or Ge (germanium), and compound semiconductors, e.g., group II-VI and group III-V compound semiconductor materials.

Epitaxial methods and templates grown by the methods

Methods which can be applied during the epitaxial growth of semiconductor structures and layers of III-nitride materials so that the qualities of successive layers are successively improved. An intermediate epitaxial layer is grown on an initial surface so that growth pits form at surface dislocations present in the initial surface. A following layer is then grown on the intermediate layer according to the known phenomena of epitaxial lateral overgrowth so it extends laterally and encloses at least the agglomerations of intersecting growth pits. Preferably, prior to growing the following layer, a discontinuous film of a dielectric material is deposited so that the dielectric material deposits discontinuously so as to reduce the number of dislocations in the laterally growing material. The methods of the invention can be performed multiple times to the same structure. Also, semiconductor structures fabricated by these methods.

Methods for improving the quality of structures comprising semiconductor materials

The invention provides methods which can be applied during the epitaxial growth of two or more layers of semiconductor materials so that the qualities of successive layer are successively improved. In preferred embodiments, surface defects present in one epitaxial layer are capped with a masking material. A following layer is then grown so it extends laterally above the caps according to the known phenomena of epitaxial lateral overgrowth. The methods of the invention can be repeated by capping surface defects in the following layer and then epitaxially growing a second following layer according to ELO. The invention also includes semiconductor structures fabricated by these methods.

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Tempe, AZ, United States of America

Ilsu Han