Radiation detecting device using superconducting tunnel junction and method of fabricating the same

A radiation detecting device comprising:

• a substrate;
• a superconducting tunnel junction having a three-layer structure formed by depositing, on said substrate in sequence, an upper electrode, a tunnel barrier layer, and a lower electrode, wherein at least one of said upper electrode and said lower electrode is made of a superconducting material;
• and
• an excited electron absorption layer made of one of a superconducting material having an energy gap smaller than that of the superconducting material forming at least one of said upper electrode and said lower electrode, a normal conducting metal having no energy gap, and a semimetal, the excited electron absorption layer being formed in a position disposed within one of said upper electrode and said lower electrode and isolated from said tunnel barrier layer.

A radiation detecting device comprising:

• a substrate;
• a superconducting tunnel junction having a three-layer structure formed by depositing, on said substrate in sequence, a lower electrode, a tunnel barrier layer, and an upper electrode, at least one of said electrode and said lower electrode is made of a superconducting material;
• a phonon absorption layer made of either a superconducting material having an energy gap smaller than that of the superconducting material forming at least one of said upper electrode and said lower electrode, or a normal conducting metal having no energy gap, said phonon absorption layer being formed between said substrate and said junction and having a thickness of at least 20 nm;
• and
• an insulating layer formed between formed between said phonon absorption layer and said junction and having a thickness greater than 20 nm and less than 20 .mu.m.

A radiation detecting device including a superconducting tunnel junction, comprising:

• a lower electrode layer;
• an upper electrode layer;
• and
• a tunnel barrier layer between and in contact with said upper electrode layer and said lower electrode layer;
• wherein said lower electrode layer, said upper electrode layer, and said tunnel barrier layer having substantially similar cross-sectional areas in plane parallel to said lower electrode layer, said upper electrode layer, and said tunnel barrier layer such that no portion of said lower electrode or said upper electrode extends beyond said tunnel barrier layer;
• and wherein at least one of said lower electrode layer and said upper electrode layer is made of a superconducting material.