Light receiving element array having a laminated semiconductor structure and manufacturing method therefor
A light receiving element array includes a substrate and a laminated semiconductor structure that is formed on the substrate. The laminated semiconductor structure includes a light absorbing layer that is disposed above the substrate and a plurality of window layers of a first conductivity type that are formed apart from each other on the light absorbing layer. Inside the laminated semiconductor structure, there is formed, for each window layer, a first of second conductivity type region that extends into the light absorbing layer from a surface of the window layer at an opposite side to the light absorbing layer. Inside the light absorbing layer, there is formed a second of second conductivity type region that is disposed such as to surround each of the plurality of window layers in plan view and extends from a surface of the light absorbing layer at an opposite side to the substrate toward a surface of the light absorbing layer at the substrate side.
1 . A light receiving element array comprising:
a substrate; and
a laminated semiconductor structure that is formed on the substrate;
wherein:
the laminated semiconductor structure includes
a light absorbing layer that is disposed above the substrate, and
a plurality of window layers of a first conductivity type that are formed apart from each other on the light absorbing layer,
there is formed, inside the laminated semiconductor structure, for each window layer, a first region of a second conductivity type that extends into the light absorbing layer from a surface of the window layer at an opposite side to the light absorbing layer, and
there is formed, inside the light absorbing layer, a second region of the second conductivity type that is disposed such as to surround each of the plurality of window layers in plan view and extends from a surface of the light absorbing layer at an opposite side to the substrate toward a surface of the light absorbing layer at a substrate side,
the light receiving element array includes an insulating film that covers an exposed surface of the light absorbing layer, an exposed surface of the window layers, exposed surfaces of the first region of the second conductivity type and exposed surfaces of the second region of the second conductivity type, and
a groove extending along the second region of the second conductivity type is formed on an upper surface of the insulating film above the second region of the second conductivity type.
2 . The light receiving element array according to claim 1 , wherein a surface of the light absorbing layer at the opposite side to the substrate is defined as a first surface, a surface of the light absorbing layer at the substrate side is defined as a second surface, and the second of second conductively type region extends from the first surface to an intermediate portion between the first surface and the second surface of the light absorbing layer.
3 . The light receiving element array according to claim 1 , wherein the second region of the second conductivity type penetrates through the light absorbing layer.
4 . The light receiving element array according to claim 1 , comprising:
a plurality of first electrodes that are provided for each window layer and disposed on the insulating film; and
wherein each first electrode is electrically connected to a corresponding first of second conductivity type regions.
5 . The light receiving element array according to claim 4 , wherein the insulating film is an antireflection film that prevents reflection of light of a wavelength set in advance.
6 . The light receiving element array according to claim 4 , wherein the first electrodes are of endless shapes in plan view.
7 . The light receiving element array according to claim 1 , comprising: a second electrode that is formed on a second main surface of the substrate.
8 . The light receiving element array according to claim 1 , wherein the plurality of window layers are disposed in a matrix in plan view.
9 . The light receiving element array according to claim 1 , wherein the laminated semiconductor structure includes a buffer layer of the first conductivity type that is formed between the substrate and the light absorbing layer.
10 . The light receiving element array according to claim 9 , wherein the buffer layer has an exposed surface at a portion of a surface at an opposite side to the substrate and
a third electrode is formed on the exposed surface.
11 . The light receiving element array according to claim 9 , wherein
the substrate is an n-type InP substrate,
the buffer layer is an n-type InP layer,
the light absorbing layer is a non-doped InGaAs layer, and
the window layers are n-type InP layers.
12 . The light receiving element array according to claim 1 , wherein
the substrate is an n-type InP substrate,
the light absorbing layer is a non-doped InGaAs layer, and
the window layers are n-type InP layers.
13 . A light receiving element array comprising:
a substrate; and
a laminated semiconductor structure that is formed on the substrate;
wherein:
the laminated semiconductor structure includes
a light absorbing layer that is disposed above the substrate, and
a plurality of window layers of a first conductivity type that are formed apart from each other on the light absorbing layer,
there is formed, inside the laminated semiconductor structure, for each window layer, a second conductivity type region that extends into the light absorbing layer from a surface of the window layer at an opposite side to the light absorbing layer, and
there is formed, inside the light absorbing layer, a separating groove that is disposed so as to surround each of the plurality of window layers in plan view and extends from a surface of the light absorbing layer at an opposite side to the substrate toward a surface of the light absorbing layer at a substrate side, and
the light receiving element array includes an insulating film that covers a bottom surface and side surfaces of the separating groove.
14 . The light receiving element array according to claim 13 , wherein the separating groove penetrates through the light absorbing layer.
15 . The light receiving element array according to claim 13 ,
wherein the insulating film covers the plurality of window layers; and
the light receiving element array includes a plurality of first electrodes that are provided for each window layer and disposed on the insulating film; and
wherein each first electrode is electrically connected to a corresponding second conductivity type region.
16 . The light receiving element array according to claim 15 , wherein the insulating film is an antireflection film that prevents reflection of light of a wavelength set in advance.
17 . The light receiving element array according to claim 15 , wherein the first electrodes are of endless shapes in plan view.