Method of field-controlled diffusion and devices formed thereby
AssigneePalo Alto Research Center Incorporated
InventorsPeter Kiesel, Oliver Schmidt
Life of this patent
Estimating the term…
Abstract
A technique for creating high quality Schottky barrier devices in doped (e.g., Li+) crystalline metal oxide (e.g., ZnO) comprises field-controlled diffusion of mobile dopant atoms within the metal oxide crystal lattice. When heated (e.g., above 550 K) in the presence of an electric field (e.g., bias to ground of +/−50 V) the dopant atoms are caused to collect to form an ohmic contact, leaving a depletion region. The size of the depletion region controls the thickness of the Schottky barrier. Metal-semiconductor junction devices such as diodes, photo-diodes, photo-detectors, MESFETs, etc. may thereby be fabricated.
Claims15
A method of fabricating a semiconductor structure to include a Schottky barrier in which a population of mobile p-type dopants are disposed within a bulk or epitaxial metal oxide structure, comprising the steps of:
- elevating the temperature of the metal oxide structure;
- creating an electric field within a first selected region of the metal oxide structure such that at least a portion of the mobile p-type dopants migrate from a second selected region of the structure which is outside said electric field toward said first selected region of the structure within said electric field, thereby creating a depletion region in said second selected region;
- and
- removing the electric field and lowering the temperature of the metal oxide structure such that the migrated mobile p-type dopants remain in their migrated locations, whereby at least a portion of said second selected region becomes one portion of a Schottky barrier, and further whereby exposure of the structure to light in order to cause the mobile p-type dopants to migrate is not performed.
A method of fabricating a metal-semiconductor structure to include a Schottky barrier, comprising:
- providing a metal oxide structure having mobile p-type dopant ions introduced therein;
- forming first and second contact structures on a first surface of said metal oxide structure;
- elevating the temperature of said metal oxide structure;
- creating an electric field within said metal oxide structure by establishing a voltage potential between the first and second contact structures, said electric field present while said metal oxide structure is at said elevated temperature, such that said mobile p-type dopant ions are caused to migrate toward a first region of said metal oxide structure proximate said first contact structure and away from a second region of said metal oxide structure proximate said second contact structure;
- and
- removing said electric field and lowering the temperature of the metal oxide structure such that the migrated dopant ions remain in the locations to which they have migrated, whereby at least a portion of said second region proximate said second contact structure becomes one portion of a Schottky barrier, and further whereby exposure of the structure to light in order to cause the mobile p-type dopants to migrate is not performed.
Dependencies are inferred from the claim text.