CN-122000784-A - Optical semiconductor device

Abstract

The present disclosure can obtain an optical semiconductor device capable of preventing a decrease in frequency band. The optical modulator (2) is provided with a semiconductor layer (22) having a semiconductor layer (22) comprising a 1 st conductive layer (13), an absorption layer (23), and a2 nd conductive layer (15) formed in this order on a substrate (3), a 1 st electrode (6) connected to the 1 st conductive layer (13), and a2 nd electrode (7) connected to the 2 nd conductive layer (15). The 1 st pad (8) is connected to the 1 st electrode (6). The 2 nd bonding pad (9) is connected with the 2 nd electrode (7). The semiconductor layer (22) has a waveguide (10) and a 1 st stage and a2 nd stage (12) disposed on opposite sides of the waveguide from each other. The 1 st pad (8) and the 2 nd pad are disposed on the 1 st land (11) via an insulating film (20). A groove (27) is formed in the semiconductor layer (22) between the 1 st pad (8) and the 2 nd pad.

Inventors

• KURAMOTO KYOSUKE
• ASAMI UCHIYAMA
• ISHIMURA EITARO
• SHIMADA SEIAKI

Assignees

• 三菱电机株式会社

Dates

Publication Date

20260508

Application Date

20251016

Priority Date

20241105

Claims (10)

1. 1. An optical semiconductor device, characterized in that, The optical semiconductor device includes: a substrate; A light modulator having a semiconductor layer including a1 st conductive layer, an absorption layer, and a 2 nd conductive layer formed in this order on the substrate, a1 st electrode connected to the 1 st conductive layer, and a 2 nd electrode connected to the 2 nd conductive layer; a 1 st bonding pad connected with the 1 st electrode, and A2 nd bonding pad connected with the 2 nd electrode, The semiconductor layer has a waveguide and a1 st stage and a2 nd stage disposed opposite to each other with respect to the waveguide, The 1 st bonding pad and the 2 nd bonding pad are arranged on the 1 st platform through an insulating film, A groove is formed between the 1 st pad and the 2 nd pad and in the semiconductor layer.
2. 2. The optical semiconductor device according to claim 1, wherein, The trench penetrates the 1 st conductive type layer and the 2 nd conductive type layer.
3. 3. The optical semiconductor device according to claim 1 or 2, wherein, Further comprising a laser unit monolithically integrated with the optical modulator over the substrate, The laser section has an electrode disposed on the 1 st stage, The groove is also formed between one of the 1 st pad and the 2 nd pad, which is closer to the electrode, and the electrode.
4. 4. The optical semiconductor device according to claim 1 or 2, wherein, The groove is formed along an outer periphery of at least one of the 1 st pad and the 2 nd pad.
5. 5. The optical semiconductor device according to claim 1 or 2, wherein, The groove is formed in the whole region between the 1 st pad and the 2 nd pad.
6. 6. The optical semiconductor device according to claim 1 or 2, wherein, The optical modulator has a 1 st optical modulator and a2 nd optical modulator arranged in a traveling direction of light and electrically connected to each other in series.
7. 7. The optical semiconductor device according to claim 1 or 2, wherein, The light modulator has a plurality of light modulators, In each of the plurality of optical modulators, the groove is formed between the 1 st pad and the 2 nd pad.
8. 8. The optical semiconductor device according to claim 1 or 2, wherein, The semiconductor device further includes a dummy pad disposed on the 2 nd land and having the same height as the 1 st pad and the 2 nd pad.
9. 9. The optical semiconductor device according to claim 1 or 2, wherein, The entire groove is buried in the insulating film.
10. 10. An optical semiconductor device, characterized in that, The optical semiconductor device includes: a substrate; A light modulator having a semiconductor layer including a1 st conductive layer, an absorption layer, and a 2 nd conductive layer formed in this order on the substrate, a1 st electrode connected to the 1 st conductive layer, and a 2 nd electrode connected to the 2 nd conductive layer; a 1 st bonding pad connected with the 1 st electrode, and A2 nd bonding pad connected with the 2 nd electrode, The semiconductor layer has a waveguide and a1 st stage and a2 nd stage disposed opposite to each other with respect to the waveguide, The 1 st bonding pad and the 2 nd bonding pad are arranged on the 1 st platform through an insulating film, A high-resistance layer is formed between the 1 st pad and the 2 nd pad, the high-resistance layer being formed by implanting ions of proton, silicon, helium, or argon into the semiconductor layer.

Description

Optical semiconductor device Technical Field The present disclosure relates to an optical semiconductor device. Background An optical semiconductor device is proposed in which a laser unit and an optical modulator are monolithically integrated (for example, see patent document 1). The optical modulator performs a differential action by a differential voltage applied between the anode pad and the cathode pad. By disposing the anode pad and the cathode pad of the optical modulator on the same side of the mesa (terrace) with respect to the waveguide, the lengths of wires connected to the two pads can be made the same. Patent document 1 Japanese patent No. 5891920 Since a leakage current flows between the two pads of the optical modulator when the differential operation is performed, a voltage applied to the absorption layer of the optical modulator is reduced. Since the leakage current flows through the capacitance below the electrode of the optical modulator, the higher the frequency, the higher the leakage current, and the lower the extinction ratio. As a result, there is a problem that the frequency band in which the optical modulator can operate normally decreases. Disclosure of Invention The present disclosure has been made to solve the above-described problems, and an object thereof is to obtain an optical semiconductor device capable of preventing a reduction in the frequency band. The optical semiconductor device according to the present disclosure includes a substrate, an optical modulator having a semiconductor layer including a1 st conductive layer, an absorption layer, and a2 nd conductive layer formed in this order on the substrate, a1 st electrode connected to the 1 st conductive layer, and a2 nd electrode connected to the 2 nd conductive layer, a1 st pad connected to the 1 st electrode, and a2 nd pad connected to the 2 nd electrode, wherein the semiconductor layer has a waveguide, a1 st land and a2 nd land disposed on opposite sides of the waveguide from each other, the 1 st pad and the 2 nd pad are disposed on the 1 st land via an insulating film, and a groove is formed between the 1 st pad and the 2 nd pad, and the semiconductor layer. In the present disclosure, a groove is formed in the semiconductor layer between the 1 st pad and the 2 nd pad. The leakage current path between the two is broken by the groove, so that the leakage current is reduced, and thus the response in a high frequency region is improved in particular. As a result, the reduction of the frequency band can be prevented. Drawings Fig. 1 is a plan view showing an optical semiconductor device according to embodiment 1. Fig. 2 is a cross-sectional view of the laser section taken along A-A ́ of fig. 1. Fig. 3 is a cross-sectional view of the light modulator taken along B-B ́ of fig. 1. Fig. 4 is a cross-sectional view of the light modulator taken along C-C ́ of fig. 1. Fig. 5 is a sectional view taken along D-D ́ of fig. 1. Fig. 6 is a cross-sectional view taken along E-E ́ of fig. 1. Fig. 7 is a plan view showing an optical semiconductor device according to a comparative example. Fig. 8 is a cross-sectional view taken along A-A ́ of fig. 7. Fig. 9 is a graph showing frequency response characteristics of embodiment 1 and the comparative example. Fig. 10 is a plan view showing an optical semiconductor device according to embodiment 2. Fig. 11 is a cross-sectional view taken along A-A ́ of fig. 10. Fig. 12 is a graph showing frequency response characteristics of embodiment 2 and the comparative example. Fig. 13 is a plan view showing an optical semiconductor device according to embodiment 3. Fig. 14 is a plan view showing an optical semiconductor device according to embodiment 4. Fig. 15 is a plan view showing modification 1 of the optical semiconductor device according to embodiment 4. Fig. 16 is a plan view showing modification 2 of the optical semiconductor device according to embodiment 4. Fig. 17 is a plan view showing an optical semiconductor device according to embodiment 5. Fig. 18 is a cross-sectional view of the 1 st light modulator taken along A-A ́ of fig. 17. Fig. 19 is a cross-sectional view of the 2 nd light modulator taken along B-B ́ of fig. 17. Fig. 20 is a plan view showing an optical semiconductor device according to embodiment 6. Fig. 21 is a plan view showing an optical semiconductor device according to embodiment 7. Fig. 22 is a cross-sectional view showing an optical semiconductor device according to embodiment 8. Fig. 23 is a plan view showing an optical semiconductor device according to embodiment 9. Fig. 24 is a cross-sectional view taken along A-A ́ of fig. 23. Description of the reference numerals A laser section; optical modulators, 2 a..1 optical modulators, 2 b..2 optical modulators, 3..semi-insulating InP substrate (substrate), 4..cathode electrode (electrode), 6..cathode electrode (1 st electrode), 7..anode electrode (2 nd electrode), 8..cathode pad (1 st pad), 9..anode pad (2 nd pad), 10..wavegui