| 英文摘要
| In this paper, the fabrication process and photoelectric characteristics of short wavelength infrared detector are analyzed. We have designed two detectors with bandgap of 1.9 μm and 2.2 μm respectively. We used InGaAs as an absorption layer and developed InAsP on the N + InP substrate by metamorphic growth. Zinc diffusion, lithography and metal deposition processes are used to develop multiple layers of step-graded buffers into strain-free, short-wavelength infrared band detector InAsP/InGaAs PIN diode. We used TEM cross-section imaging to study the thickness of InAsP metamorphic buffer layer and InGaAs absorption layer. The photoelectric characteristics of components were tested with Photoluminescence spectrum (PL), Spectral response, I-V curve and C-V curve at room temperature.
In TEM (110) section, we found that this structure will limit the misfit dislocations in the buffer layer, and threading dislocation was not observed in the absorption layer. We obtained energy gap of InGaAs absoprtion layer and the bowing parameter C of InGaAs alloy with PL in 300K. Then we used the response spectrum to measure devices’ light responsivity, cut-off wavelength and quantum efficiency. We measured the I-V curve and fitted them with the theoretical current formula. Through the calculation of I-V curve, we obtained the detectivity and R0A of the device. In addition, we also measured the C-V curve of the device, and deduced the equivalent circuit of the element based on the MOS theory. The measured C-V is not affected by the defect, the built-in potential and doping concentration of the device are also calculated. |
