Infrared detection device, infrared detection apparatus, and manufacturing method of infrared detection device
An infrared detection device includes a semiconductor substrate; a first metamorphic buffer layer that is formed on the semiconductor substrate; a first contact layer that is formed on the first metamorphic buffer layer; a first infrared absorption layer that is formed on the first contact layer; a second contact layer that is formed on the first infrared absorption layer; a second metamorphic buffer layer that is formed on the second contact layer; a third contact layer that is formed on the second metamorphic buffer layer; a second infrared absorption layer that is formed on the third contact layer; a fourth contact layer that is formed on the second infrared absorption layer; a lower electrode that is connected with the first contact layer; an upper electrode that is connected with the fourth contact layer; and an intermediate electrode that is connected with the second contact layer and the third contact layer.
1. An infrared detection device comprising:
a semiconductor crystal substrate;
a first metamorphic buffer layer that is formed on the semiconductor crystal substrate;
a first contact layer that is formed on the first metamorphic buffer layer;
a first infrared absorption layer that is formed on the first contact layer;
a second contact layer that is formed on the first infrared absorption layer;
a second metamorphic buffer layer that is formed on the second contact layer;
a third contact layer that is formed on the second metamorphic buffer layer;
a second infrared absorption layer that is formed on the third contact layer;
a fourth contact layer that is formed on the second infrared absorption layer;
a lower electrode that is connected with the first contact layer;
an upper electrode that is connected with the fourth contact layer; and
an intermediate electrode that is connected with the second contact layer and the third contact layer.
2. The infrared detection device according to claim 1 , wherein
the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer are doped with an impurity element that makes the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer become n-type.
3. The infrared detection device according to claim 1 , wherein
the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer are doped with an impurity element that makes the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer become p-type.
4. The infrared detection device according to claim 1 , further comprising:
a first hole that is formed by removing the fourth contact layer, the second infrared absorption layer, the third contact layer, the second metamorphic buffer layer, the second contact layer, and the first infrared absorption layer; and
a second hole that is formed by removing the fourth contact layer, the second infrared absorption layer, the third contact layer, and the second metamorphic buffer layer, wherein
an insulating film is formed on a side surface of the first hole and a side surface of the second hole,
the lower electrode is formed on the first contact layer of a bottom surface of the first hole and on the insulating film of the side surface of the first hole,
the second hole includes a wide width region that is formed by removing the fourth contact layer and the second infrared absorption layer and a narrow width region that is narrower than the wide width region and is formed by removing the third contact layer of a bottom surface of the wide width region and the second metamorphic buffer layer, and
the intermediate electrode is formed on the second contact layer of a bottom surface of the second hole, on the third contact layer of a bottom surface of the second hole, and on the insulating film of the side surface of the second hole.
5. The infrared detection device according to claim 1 , wherein
the first contact layer, the first infrared absorption layer, and the second contact layer are formed of InAs X Sb 1-X and X is set such that 0.8≤X≤1.0, and
the third contact layer, the second infrared absorption layer, and the fourth contact layer are formed of InAs Y Sb 1-Y and Y is set such that 0≤Y<0.8.
6. The infrared detection device according to claim 1 , wherein
a lattice constant of the second infrared absorption layer and a lattice constant of the first infrared absorption layer satisfy
0.1%≤(the lattice constant of the second infrared absorption layer−the lattice constant of the first infrared absorption layer)/(the lattice constant of the first infrared absorption layer)≤6.97%.
7. The infrared detection device according to claim 1 , wherein
a first barrier layer is formed between the first contact layer and the first infrared absorption layer, and
a second barrier layer is formed between the second infrared absorption layer and the fourth contact layer.
8. The infrared detection device according to claim 7 , wherein
the first barrier layer is formed of AlSb, and
the second barrier layer is formed of InAlSb.
9. The infrared detection device according to claim 1 ,
wherein a thickness of the second metamorphic buffer layer is 1000 nm or greater.
10. An infrared detection apparatus comprising:
an infrared detection device that includes:
a semiconductor crystal substrate,
a first metamorphic buffer layer that is formed on the semiconductor crystal substrate,
a first contact layer that is formed on the first metamorphic buffer layer,
a first infrared absorption layer that is formed on the first contact layer,
a second contact layer that is formed on the first infrared absorption layer,
a second metamorphic buffer layer that is formed on the second contact layer,
a third contact layer that is formed on the second metamorphic buffer layer,
a second infrared absorption layer that is formed on the third contact layer,
a fourth contact layer that is formed on the second infrared absorption layer,
a lower electrode that is connected with the first contact layer,
an upper electrode that is connected with the fourth contact layer, and
an intermediate electrode that is connected with the second contact layer and the third contact layer; and
a signal read-out circuit element that is connected with the infrared detection device.
11. The infrared detection apparatus according to claim 10 , wherein
the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer are doped with an impurity element that makes the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer become n-type.
12. The infrared detection apparatus according to claim 10 , wherein
the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer are doped with an impurity element that makes the first contact layer, the second contact layer, the third contact layer, and the fourth contact layer become p-type.
13. The infrared detection apparatus according to claim 10 , further comprising:
a first hole that is formed by removing the fourth contact layer, the second infrared absorption layer, the third contact layer, the second metamorphic buffer layer, the second contact layer, and the first infrared absorption layer; and
a second hole that is formed by removing the fourth contact layer, the second infrared absorption layer, the third contact layer, and the second metamorphic buffer layer, wherein
an insulating film is formed on a side surface of the first hole and a side surface of the second hole,
the lower electrode is formed on the first contact layer of a bottom surface of the first hole and on the insulating film of the side surface of the first hole,
the second hole includes a wide width region that is formed by removing the fourth contact layer and the second infrared absorption layer and a narrow width region that is narrower than the wide width region and is formed by removing the third contact layer of a bottom surface of the wide width region and the second metamorphic buffer layer, and
the intermediate electrode is formed on the second contact layer of a bottom surface of the second hole, on the third contact layer of a bottom surface of the second hole, and on the insulating film of the side surface of the second hole.
14. A manufacturing method of an infrared detection device, the manufacturing method comprising:
laminating, sequentially, a first metamorphic buffer layer, a first contact layer, a first infrared absorption layer, a second contact layer, a second metamorphic buffer layer, a third contact layer, a second infrared absorption layer, and a fourth contact layer on a semiconductor crystal substrate;
forming a first hole, in which the first contact layer is exposed on a bottom surface, by removing the fourth contact layer, the second infrared absorption layer, the third contact layer, the second metamorphic buffer layer, the second contact layer, and the first infrared absorption layer;
forming a wide width region of a second hole, in which the third contact layer is exposed on a bottom surface, by removing the fourth contact layer and the second infrared absorption layer;
forming a narrow width region of the second hole, in which the second contact layer is exposed on a bottom surface, by removing the third contact layer and the second metamorphic buffer layer in the bottom surface of the wide width region;
forming an insulating film on side surfaces of the first hole and the second hole; and
forming a lower electrode that is connected with the first contact layer in the first hole, an intermediate electrode that is connected with the third contact layer and the second contact layer in the second hole, and an upper electrode on the fourth contact layer.