Fabrication, characterization and integration of oxide passivated nanocrystalline silicon light emitting devices

System integration in microelectronics has progressed to the point where complete "system-on-a-chip" applications are realized. Unfortunately crystalline silicon, an indirect bandgap semiconductor, is an inefficient light-emitting material which impedes integration capabilities with optoelectronics. Over the last decade a tremendous engineering effort has been invested in LEDs based on porous silicon (PSi), with only limited success. Although PSi can exhibit efficient room-temperature visible photoluminescence, the comparatively low LED electroluminescence (EL) efficiency (EQE < 0.2%) clearly identifies electrical excitation as a challenge, while suggesting that through device engineering the efficiency may approach that required for commercial applications.; This report presents details of LED structures based on oxide passivated nanocrystalline silicon (OPNSi), formed by oxidation of PSi. OPNSi can be best described as a porous glass structure with defects that facilitate transport, and remaining embedded nanocrystals of silicon that support light emission. This material, like its PSi precursor, can luminesce quite efficiently while demonstrating several advantages in stability (i.e. chemical, thermal, electrical and EL). The effort in process and device engineering has resulted in the fabrication of OPNSi LEDs that offer many of the required attributes of a useful silicon light-emitter. The devices exhibit uniform emission over the LED contact area at a bias ∼6V, diode-like rectifying I-V characteristics, good stability under DC bias, and modulation capability exceeding MHz. This study provides a thorough analysis of the OPNSi material, and the OPNSi LED structure. Extensive electrical characterization of OPNSi LEDs has enabled the development of a comprehensive transport model that is self-consistent will all experimental observations. Characterization of EL has confirmed that the contribution of nanocrystalline silicon to the mechanisms of light emission is significant.; The demonstration of successful integration of the LEDs into a bipolar technology has verified the compatibility of the devices with standard integrated circuit processing techniques. Further progress in device engineering and integration has resulted in a CMOS-compatible fabrication technique which enables the formation of electrically isolated integrated LEDs in the single-crystal substrate. The coupling of silicon-based light-emitting technology and microelectronic circuits may eventually enhance system integration to levels well beyond the limits of today.