Silicon avalanche light-emitting devices (Si Av LEDs) offer various possibilities for realizing micro- and even nano- optical biosensors directly on chip. The light-emitting devices (LEDs) operate in the wavelength range of about 450-850nm, and their optical power emitted is of the order of a few hundreds of nW/µm². These LEDs could be fabricated in micro- and nano- dimensions by using modern semiconductor fabrication processing technologies through the mainstream of silicon material. Through a series of experiments, the dispersion phenomena in the Si Av LED are observed. Also, its light emission point was proved to locate at about one micron just below the silicon-silicon oxide interface. Subsequently, a micro-fluidic channel sensor was designed by using the dispersion characteristics owned by the Si Av LED. The analytes flowing through a micro-fluidic channel could be studied by their specific transmittance and absorption spectra. Moreover, simulations verify that a novel designed waveguide-based sensor could be fabricated on chip between the Si optical source and the Si P-I-N detector.

A silicon light emitting device was designed and realized utilizing a standard 2-/spl mu/m industrial CMOS technology design and processing procedure. The device and its associated driving circuitry were integrated in a CMOS integrated circuit and can interface with a multimode optical fiber. The device delivers 8 nW of optical power (450-850 nm wavelength) per 20-/spl mu/m diameter of chip area at 4.0 V and 5 mA. The device emits light by means of a surface assisted Zener breakdown process that occurs laterally between concentrically arranged highly doped n/sup +/ rings and a p/sup +/ centroid, which are all coplanarly arranged with an optically transparent Si-SiO/sub 2/ interface. Theoretical and experimental determinations with capacitances and series resistances indicate that the device has an intrinsic high-frequency operating capability into the near gigahertz range.

A number of planar silicon light-emitting devices are designed and realized in standard 1.2 and 2-μm complementary metal oxide semiconductor (CMOS) integrated circuitry. The devices yield optical power intensities of up to 0.2 μW/cm² (up to 0.2 nW per 100 μm²) at operating voltages from 4 to 31 V and at currents of 0.1 to 10 mA, respectively. The devices emit light in a broad spectrum from 450 to 800 nm with characteristic peaks at 500 and 650 nm. The emitted intensity of the devices is three to four orders of magnitude higher than the low-frequency detectability limit of integrated Si optical pn detectors utilizing similar areas on chip as the light sources. Initial investigations indicate that the devices have a very fast inherent modulation bandwidth capability. The devices show potential for on-chip electro-optical communication and chip-to-chip electro-optical communications. © 2002 Society of Photo-Optical Instrumentation Engineers.

Scaled versions of a variety of silicon light-emitting diode elements (Si LEDs) have been realized using a standard 1.2-μm, double-polysilicon, double-metal, n-well CMOS fabrication process. The devices operated with a n⁺p junction biased in the avalanche breakdown mode and were realized by using standard features of the ORBIT FORESIGHT design rules. The elements emit optical radiation in a broad band in the 450- to 850-nm range. An emitted intensity (radiant exitance) of up to 7.1 μW/cm² (or about 8 nW per 60-μm-diam chip area) has been obtained with 5 mA of current at an operating voltage of 18.5 V. Excellent uniformity in emission intensity of better than 1% variation was obtained over areas as large as 100×500 μm. A best power conversion efficiency of 8.7×10⁻⁸ and a quantum efficiency of 7.8×10⁻⁷ were measured. All of these values are about one order of magnitude better than previously reported values for Si LED avalanche devices. Coupling between the elements as well as electro-optical coupling between an element and an optical fiber was realized. © 1998 Society of Photo-Optical Instrumentation Engineers.