Optical semiconductor device and optical transmission apparatus
An apparatus includes a first semiconductor layer including a first bandgap; and a second semiconductor layer of a first polarity including a second bandgap smaller than the first bandgap and formed over the first semiconductor layer. The first semiconductor layer includes a first conductive region of the first polarity, a second conductive region of a second polarity, and a non-conductive region between the first conductive region and the second conductive region, and the second semiconductor layer is in contact with the first conductive region and the non-conductive region.
1. An apparatus comprising:
a first semiconductor layer including a first bandgap;
a second semiconductor layer of a first polarity including a second bandgap smaller than the first bandgap, and formed over the first semiconductor layer;
a first insulation layer in contact with an upper surface of the second semiconductor layer; and
a second insulation layer in contact with a side surface of the second semiconductor layer,
wherein the first semiconductor layer includes
a first conductive region of the first polarity,
a second conductive region of a second polarity, and
a non-conductive region between the first conductive region and the second conductive region, the non-conductive region being in contact with the second conductive region.
2. The apparatus of claim 1 , further comprising:
a first metal film in ohmic contact with the first conductive region; and
a second metal film in ohmic contact with the second conductive region.
3. The apparatus of claim 2 ,
wherein the first conductive region includes
a third conductive region in contact with the first metal film, and
a fourth conductive region in contact with the non-conductive region, and
the third conductive region contains a p-type impurity at a concentration higher than a concentration of the fourth conductive region.
4. The apparatus of claim 1 ,
wherein a recess is formed in a region of the first semiconductor layer that is in contact with the second semiconductor layer.
5. The apparatus of claim 1 , further comprising:
a photoelectric converter in which the first semiconductor layer and the second semiconductor layer overlap with each other in plan view; and
a mode converter coupled to the photoelectric converter,
wherein in the mode converter, the first semiconductor layer has a planar shape of which a width increases as approaching the photoelectric converter.
6. The apparatus of claim 5 , wherein the width is a direction perpendicular to an incident direction of the light to the photoelectric converter.
7. The apparatus of claim 1 ,
wherein the first polarity is a p-type, and
the second polarity is an n-type.
8. The apparatus of claim 1 ,
wherein the first semiconductor layer is an Si layer, and
the second semiconductor layer is a Si x Ge 1-x layer (0≤x<1).
9. The apparatus of claim 1 ,
wherein the first semiconductor layer is an Si layer, and
the second semiconductor layer is a Ge 1-x Sn x layer (0≤x<1).
10. The apparatus of claim 1 , wherein an interface between the second semiconductor layer acts as a diffusion blocking layer for electrons to guide the electrons to the second conductive region.
11. The apparatus of claim 1 , wherein a metal film does not contact the second semiconductor layer.
12. The apparatus of claim 1 , wherein the second semiconductor layer is in electrical and mechanical contact with a portion of the first semiconductor layer.
13. The apparatus of claim 1 , wherein the apparatus is a (Silicon) Si photonic optical semiconductor device.
14. The apparatus of claim 1 , wherein the light is introduced into the first polarity region of the second semiconductor, and the photo carrier is generated inside the region.
15. The apparatus of claim 1 , wherein the second semiconductor layer contains Boron at a concentration of 0.5×10 19 cm −3 to 2.5×10 19 cm −3 .
16. A (Silicon) Si photonic optical semiconductor device comprising:
a plurality of light receivers, each of the plurality of light receivers includes a plurality of uni-traveling-carrier photo diodes (UTC-PD), each UTC-PD includes:
a first semiconductor layer including a first bandgap; and
a second semiconductor layer of a first polarity including a second bandgap smaller than the first bandgap, and formed over the first semiconductor layer;
a first insulation layer in contact with an upper surface of the second semiconductor layer; and
a second insulation layer in contact with a side surface of the second semiconductor layer,
wherein the first semiconductor layer includes
a first conductive region of the first polarity,
a second conductive region of a second polarity, and
a non-conductive region between the first conductive region and the second conductive region, the non-conductive region being in contact with the second conductive region.
17. A method of manufacturing a (Silicon) Si photonic optical semiconductor device, the method comprising:
forming a first semiconductor layer including a first bandgap, the first semiconductor layer having a first conductive region of a first polarity, a second conductive region of a second polarity, and a non-conductive region between the first conductive region and the second conductive region, the non-conductive region being in contact with the second conductive region; and
forming a second semiconductor layer of the first polarity including a second bandgap smaller than the first bandgap, the second semiconductor layer being formed over the first semiconductor layer;
forming a first insulation layer in contact with an upper surface of the second semiconductor layer; and
forming a second insulation layer in contact with a side surface of the second semiconductor laver.