Method of forming, modifying, or repairing a semiconductor device using field-controlled diffusion
View Patent ↗A technique for altering or repairing the operating state of a semiconductor device 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. Metal-semiconductor junction devices such as diodes, photo-diodes, photo-detectors, MESFETs, etc. may thereby be fabricated, repaired or modified.
1. A method for modifying the electrical characteristics of a semiconductor device to a desired state, the semiconductor device of a type having a metal oxide structure and a population of mobile carrier atoms of a first charge type disposed within said metal oxide structure, said mobile carrier atoms having been caused to migrate to desired regions of the metal oxide structure, comprising the steps of:
elevating the temperature of the device;
creating an electric field within a first region of the metal oxide structure of the device such that at least a portion of the mobile carrier atoms migrate from a second region of the structure which is outside said electric field toward said first region of the metal oxide structure, thereby creating a depletion region in said second region; and
removing the electric field and lowering the temperature of the metal oxide structure such that the migrated mobile carrier atoms remain in the locations to which they migrated, and further such that the location to which the carrier atoms migrated results in the modification of the electrical characteristics of the device to the desired state;
whereby exposure of the structure to light in order to cause the mobile carrier atoms to migrate is not performed.
2. The method of claim 1 , wherein the method repairs damage to the semiconductor device such that the semiconductor device is returned to a prior operating condition.
3. The method of claim 1 , wherein the method alters the operating condition of the semiconductor device to an operating condition different from the operating condition of the semiconductor device as originally formed.