Silicon LEDs fabricated in standard VLSI technology as components for all silicon monolithic integrated optoelectronic systems

Abstract

It is shown that, by using conventional VLSI design rules and device processing, a variety of two terminal and multiterminal integrated silicon light-emitting devices (Si-LEDs) can be routinely fabricated without any adaptation to the process, enabling the production of all-silicon monolithic optoelectronic systems. Their specific performance can be tailored by their different geometries and structures, yielding, by design, area, line, and point light-emitting patterns. The light-generating mechanisms are based on carrier quantum transitions in Si pn junctions, operated in the field emission or avalanche modes. Field emission Si-LEDs can operate at supply voltages compatible with those of integrated circuits (5 V or less). Avalanche Si-LEDs require higher operating voltages, but yield higher light intensities. The two terminal Si-LEDs yield a linear relation between the emitted light intensity and the driving current. The multiterminal Si-LEDs exhibit a nonlinear relation between the light emission intensity and the controlling electrical signal, enabling signal processing operations, which can not be attained in two terminal Si-LEDs. Two basic structures of multi terminal Si-LEDs are presented, i.e MOS-like structures, or carrier injection based structures (BJT-like devices). They possess different input impedances and both their emitted light intensities and emitting area patterns can be controlled by the input electrical signal.