A method of manufacturing at least one switching device, comprising one of a first step sequence and a second step sequence, the method comprising:
- the first step sequence comprising:
- (1) obtaining a base structure having a planar surface and comprising a first electrode which is flush with the planar surface,
- (2) forming a layer of an active material on the planar surface of the base structure, the active material being capable of switching from an electrically insulating state to an electrically conducting state when a voltage higher than a threshold value is applied between two opposing surfaces of the layer of the active material,
- (3) removing the layer of the active material selectively outside an area which is located above the first electrode, such that a portion of the active material remains on the first electrode,
- (4) depositing a dielectric material on the base structure, such that the portion of the active material is embedded within the dielectric material,
- (5) polishing the dielectric material such that the portion of the active material is flush with a planar abrasion surface of the dielectric material on a side opposite to the base structure, and
- (6) forming a second electrode on the portion of the active material on the side opposite to the base structure;
- and
- the second step sequence comprising:
- (1′) obtaining a base structure having a planar surface and comprising a first electrode which is flush with the planar surface,
- (2′) depositing a layer of dielectric material on the planar surface of the base structure,
- (3′) removing the layer of dielectric material selectively inside an area which is comprised in a cross-section of the first electrode parallel to the planar surface of the base structure, so as to form a cavity which extends to the first electrode,
- (4′) filling the cavity with an active material capable of switching from an electrically insulating state to an electrically conducting state when a voltage higher than a threshold value is applied between two opposing surfaces of a portion of the active material,
- (5′) polishing the active material such that the layer of the dielectric material is flush with a planar abrasion surface on a side opposite to the base structure, the cavity filled with the active material forming an active portion, and
- (6′) forming a second electrode on the active portion on the side opposite to the base structure,
- wherein the active material is varied in composition during step (2) or step (4′), such that a relative dielectric permittivity is non-uniform along a direction perpendicular to the planar surface of the base structure, or the dielectric material is varied in composition during step (4) or step (2′), such that a relative dielectric permittivity of the dielectric material is non-uniform along the direction perpendicular to the planar surface of the base structure.