Zinc Stannate Ohmic Contacts for P-Type Gallium Nitride
AssigneeIntermolecular, Inc.
InventorsJianhua Hu, Heng Kai Hsu, Tong Ju, Minh Huu Le, Sandeep Nijhawan, Teresa B. Sapirman
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Abstract
Transparent ohmic contacts to p-GaN and other high-work-function (≧4.2 eV) semiconductors are fabricated from zinc stannate (e.g., ZnSnO3). ZnO and SnO2 may be sputtered from separate targets and annealed to form the zinc stannate. The Zn:Sn ratio may be tuned over the range between 1:2 and 2:1 to optimize bandgap, work function, conductivity, and transparency for the particular semiconductor and wavelength of interest. Conductivity may be improved by crystallizing the zinc stannate, by doping with up to 5 wt % Al or In, or both.
Claims20
A device, comprising:
- a semiconductor layer having a work function greater than or equal to 4.2 eV;
- and
- a conductive layer adjacent to the semiconductor layer;
- wherein the conductive layer comprises zinc, tin, and oxygen;
- wherein a weight ratio of zinc to tin in the conductive layer is between about 1:2 and about 2:1;
- and
- wherein the conductive layer is operable as an ohmic contact to the semiconductor layer.
A method, comprising:
- providing a substrate comprising a semiconductor structure;
- and
- forming a conductive layer over the semiconductor structure;
- wherein a work function of the semiconductor structure is greater than about 4.2 eV;
- wherein the conductive layer is operable as an ohmic contact to the semiconductor structure;
- wherein the conductive layer comprises zinc, tin, and oxygen;
- and
- wherein a weight ratio of zinc to tin in the conductive layer is between about 1:2 and about 2:1.
Dependencies are inferred from the claim text.