A Promising Low Noise And High Gain Ingaas/Si Avalanche Photodiode

In this paper, the direct bonding InGaAs/Si avalanche photodiode (APD) with certain gain is developed. This structure separates the optical absorption region (InGaAs) from the multiplication region (Si). Avalanche multiplication takes place in the Si layer after the carriers injected from the absorption region. InGaAs and Si wafer are connected together by wafer bonding technology. The interface quality of InGaAs / Si material is good through optimizing the physical and chemical cleaning methods and bonding conditions of InGaAs/InP and Si epitaxial wafers. The InGaAs / Si APD is fabricated by conventional semiconductor process. The gain of InGaAs / Si APD is 43 at 38V. Further optimization of the process can obtain lower dark current and higher gain bandwidth product. This kind of device can be used for long-distance optical fiber communication.