Resonant tunneling diode, oscillator and detection system
A resonant tunneling diode includes a substrate, and a mesa structure including a compound semiconductor layer including a heterojunction comprising a multi-barrier structure disposed on the substrate, and an electrode disposed on the upper surface of the compound semiconductor layer. An outer edge portion of the compound semiconductor layer is a first region including crystal defects, and the first region and the electrode are set apart from each other.
1 . A resonant tunneling diode comprising:
a substrate;
a mesa structure including a compound semiconductor layer including a heterojunction comprising a multi-barrier structure disposed on the substrate;
an electrode disposed on an upper surface of the compound semiconductor layer, and configured to contact the upper surface of the compound semiconductor layer; and
a dielectric film,
wherein an outer edge portion of the compound semiconductor layer is a first region including crystal defects,
wherein the first region and the electrode are set apart from each other, and
wherein the dielectric film covers an area ranging from at least a part of the first region to at least a part of the electrode, and covers an upper surface of the part of the electrode.
2 . The resonant tunneling diode according to claim 1 , wherein in a cross section parallel to a thickness direction of the substrate, an outer edge of the upper surface of the compound semiconductor layer is separated from an outer edge of the electrode by a predetermined distance in a direction perpendicular to the thickness direction of the substrate.
3 . The resonant tunneling diode of claim 2 , wherein the predetermined distance is 20 nm or more.
4 . The resonant tunneling diode of claim 1 , wherein a center of the electrode and a center of the compound semiconductor layer are substantially aligned in a top view of the substrate.
5 . The resonant tunneling diode of claim 1 , wherein the dielectric film covers an area ranging at least from the first region to the electrode.
6 . The resonant tunneling diode of claim 1 , wherein the dielectric film includes silicon nitride, silicon oxide, or aluminum oxide.
7 . The resonant tunneling diode of claim 1 , wherein the electrode comprises gold and titanium, gold and palladium and titanium, gold and platinum and titanium, tungsten, molybdenum, or tantalum.
8 . The resonant tunneling diode of claim 1 , wherein the first region includes crystal defects caused by dry etching.
9 . The resonant tunneling diode of claim 1 , wherein the first region is a region including a crystal, an amorphous material, or both a crystal and an amorphous material.
10 . An oscillator, comprising:
one or a plurality of resonant tunneling diodes according to claim 1 ,
wherein the one or the plurality of resonant tunneling diodes are connected to and integrated with an antenna to form a single solid-state element structure.
11 . An oscillator, comprising:
a plurality of oscillators according to claim 10 ,
wherein the plurality of oscillators are coupled and operate in synchronization with each other.
12 . A detection system comprising:
the resonant tunneling diode according to claim 1 as an oscillation element;
a receiving element that receives a high frequency from the oscillation element; and
a processing circuit that processes a signal from the receiving element.
13 . The resonant tunneling diode of claim 1 , further comprising a second electrode.
14 . The resonant tunneling diode of claim 13 , wherein the second electrode is arranged on the dielectric film.
15 . The resonant tunneling diode of claim 14 , wherein the dielectric film has an opening, and the second electrode is arranged in the opening.