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Fabrication of waveguide InGaAs MSM Photodetector on III-V CMOS Photonics Platform
| Content Provider | Semantic Scholar |
|---|---|
| Author | Cheng, Yongpeng |
| Copyright Year | 2014 |
| Abstract | 1. Background For chip-scale optical interconnects, waveguide photodetectors (PDs) are fundamental building blocks; thus InGaAs PDs integrated with Si waveguides on the III-V/Si hybrid platform have intensely been investigated so far. However, it seems to be difficult for the III-V/Si hybrid platform to achieve monolithic integration of InGaAs PDs with Si complementary metal-oxide-semiconductor (CMOS) transistors because high-temperature processes required for Si CMOS are not acceptable to InGaAs PDs. To overcome this constraint, we have investigated the III-V CMOS photonics platform, enabling monolithic integration of InGaAs MOS transistors and InP-based photonic devices on a III-V-on-Insulator (III-V-OI) wafer. In this paper, we present a waveguide InGaAs metal-semiconductor-metal (MSM) PD on the III-V CMOS photonics platform. 2. Fabrication Firstly, we prepare a III-V-OI wafer as follows. i-InP/p-InGaAs layers are grown on an InP wafer. A 2.3-μm-thick SiO2 BOX layer is also thermally grown on a Si wafer. After depositing Al2O3 on both wafers by atomic layer deposition (ALD), the two wafers are bonded together. Finally, the InGaAs/InP on SiO2/Si wafer is obtained by etching the InP substrate. By using the III-V-OI wafer, we fabricate InGaAs MSM PD integrated monolithically integrated with an InP rib waveguide on the SiO2/Si as shown Fig. 1. First, the waveguide is defined by DUV lithography and reactive ion etching (RIE). Then, an InGaAs layer on the InP waveguide is selectively removed by wet etching. Then, an Al2O3 passivation layer is deposited by ALD. Finally, interdigitated electrodes are formed by Ni deposition and lift-off. 3. Test and discussion Firstly, 7.7dB total loss (insertion plus propagation loss) of the InP rib waveguide on the SiO2/Si wafer is obtained by the cut-back method. Then, 8-dBm CW light is injected to compensate this loss and ensure approximately 0-dBm launched power to the InGaAs PD. We evaluate photo-current and dark current as shown by Fig. 2. Since Schottky contact can be obtained between Ni and p-InGaAs, the dark current is suppressed below approximately 270nA when the bias voltage is 1V. The photocurrent at 1V bias voltage is approximately 386μA when the 1550-nm CW light with the 0-dBm launched power to the PD is injected. Thus, the Ion/Ioff ratio is approximately more than 10. When the bias voltage is increased to 2V, the photo-current of more than 1mA is obtained, resulting in the high responsivity of >1.0A/W. Acknowledgements This work was supported by Grant-in-Aid for Young Scientists (A) from MEXT. Reference |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://confit.atlas.jp/guide/event-img/jsap2014s/17p-PA2-9/public/pdf?type=in |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
