Porous pseudo-substrates for group iii-nitrides
OwnerShubhra S. Pasayat, Chirag Gupta +1inventors
InventorsShubhra S. Pasayat, Chirag Gupta, Qinchen Lin
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Abstract
Methods for fabricating group III-nitride-based pseudo-substrates are provided. Also provided are pseudo-substrates made using the methods and electronic devices incorporating the pseudo-substrates. The methods combine vertical and lateral electrochemical porosification to create a porous, compliant group III-nitride layer over which a relaxed group III-nitride layer can be regrown. The porosification of the group III-nitride increases its in-plane lattice constant enabling the epitaxial regrowth of a group III-nitride having an enhanced alloy composition. The methods preserve the surface quality of the pseudo-substrate and produce a uniform porosity across the porosified layer.
Claims20
A heterostructure comprising:
- a base substrate;
- and
- a pseudo-substrate stack on the base substrate, the pseudo-substrate stack comprising a single bilayer or a stack of two or more bilayers, each bilayer comprising:
- a compliant layer comprising a porosified n-type group III-nitride;
- and
- a layer of unintentionally doped group III-nitride on the compliant layer, the layer of unintentionally doped group III-nitride having a surface comprising one or more areas comprising etched vertical threading dislocation channels separated by one or more areas that are free of etched vertical threading dislocation channels,
- wherein the porosification of the porosified n-type group III-nitride extends continuously under the one or more areas comprising etched vertical threading dislocation channels and the one or more areas that are free of etched vertical threading dislocation channels.
A method of making a heterostructure, the method comprising:
- forming a pseudo-substrate stack on a base substrate, the pseudo-substrate stack comprising a single bilayer or a stack of two or more bilayers, each bilayer comprising:
- a layer of n-type group III-nitride;
- and
- a layer of unintentionally doped group III-nitride on the layer of n-type group III-nitride;
- forming a dielectric mask on a surface of an uppermost layer of unintentionally doped group III-nitride in the pseudo-substrate stack, wherein one or more areas of the surface of the uppermost layer of unintentionally doped group III-nitride are exposed through the dielectric mask and one or more areas of the surface of the uppermost layer of unintentionally doped group III-nitride are covered by the dielectric mask;
- carrying out vertical and lateral electrochemical porosification of the one or more layers of n-type group III-nitride in the pseudo-substrate stack in the presence of the dielectric mask to form one or more compliant layers of porosified n-type group III-nitride in the pseudo-substrate stack;
- and
- removing the dielectric mask from the surface of the uppermost layer of unintentionally doped group III-nitride.
Dependencies are inferred from the claim text.