Low Voltage, High Brightness CMOS LEDs

Silicon photonics realized in CMOS processes has transformed computing, communications, sensing and imaging. Although silicon is known as an indirect bandgap material, substantial progress has been made in the field of silicon p-n junctions emitting visible light when operating in reverse breakdown avalanching mode. Here, we demonstrate high-brightness infrared light emission in forward bias for a vertical silicon p-n junction realized in an open-foundry CMOS process – 55 BCDLite. Emission intensity of over 40 mW/cm2 light at 1020 nm is realized at below 2.5 Volt of room temperature operation by using a deep vertical junction with guard rings that ensure carrier transport away from material interfaces. Such a device enables the development of optoelectronic systems in silicon CMOS. Here, we also demonstrate a complete chip-to-chip optical interconnect utilizing only silicon CMOS devices.