Micron and Nano-Dimensioned Silicon LEDs Emitting at 650 and 750-850 nm Wavelengths in Standard Si Integrated Circuitry

Abstract

Optical transitions in silicon avalanche mode silcon LEDs were modeled, using the energy band structure, available carrier energy and momentum spreads. Based on previous experimental observations, it was hypothesized that emissions at these wavelengths can be enhanced by using a combination of excitation of carriers in high electric fields and scattering of excited carriers in compensated, high dopant impurity p+n+ environments, optical emissions at 650 and 750-850 nm wavelength emission regimes could be stimulated. A number of p+np+ devices were subsequently designed and realized using a 0.35-micron RF bipolar fabrication process that provided control over both carrier energy and carrier balancing. The optical emission characteristics of the devices was analyzed using an optical fiber lensed probe spectrophotometer and high-resolution optical microscopy. Clear evidence is obtained that 650 nm emissions can be enhanced in nano dimensioned emission spots by using these technologies. The devices operated in the 5-10V and 0.08–10mA regime. External emission intensities of up to 100 nW $\mu \text{m}^{2}$ were observed. Furthermore, using the same modeling, light emission was observed at nano-dimensioned regions emitting in the 750 - 850 nm emission region by placing high dopant impurity regions next to lowly doped high E fleld regions, and relaxing and scattering carriers in these zones. The 750 - 850 nm emissions may find application in both short haul and long haul integrated Si AMLEDs coupled to silicon nitride waveguide structures.