Geiger-Mode Avalanche Photodiode Arrays Fabricated on Silicon-on-Insulator Substrates

Avalanche photodiodes (APDs) are semiconductor devices widely used in various applications that require high-sensitivity light detection, including medical imaging, aerospace, industrial, and scientific research. Their ability to operate in Geiger mode means that they can detect even single photons, making them ideal for low-light conditions and precise measurements. There's a growing demand for photodiodes that can provide even greater sensitivity and integration with electronics to process their outputs effectively. Currently, integrating photodiodes with readout circuits can be challenging because traditional manufacturing methods may result in increased noise, limited isolation between circuits, and bulkier components, reducing image resolution and system performance. Additionally, conventional approaches often involve complex and expensive manufacturing processes to achieve a lesser degree of integration, therby limiting the deployment of such advanced devices in various markets that require high precision and reliability.

Technology Description

The invention refers to a method for creating avalanche photodiodes that operate in Geiger mode. These highly sensitive detectors are  capable of sensing single photons, and this proposed process is for manufacturing them on a separate wafer from the readout integrated circuits (ROICs) responsible for processing the signals from the photodiodes. An epitaxial layer is grown on a semiconductor-on-insulator wafer to form the photodiode arrays, which are subsequently individualized into chips and paired with corresponding ROIC chips using bump bonding techniques. The differentiation of this technology lies in its dual-wafer approach and the use of advanced bump bonding to create highly compact, integrated devices. This architecture significantly improves the efficiency of photon detection and signal processing, enabling higher resolution imaging in various applications. The use of semiconductor-on-insulator substrates further enhances device performance by reducing electrical noise and improving isolation between components.