Single photon avalanche diode on Ge-Si, dreams, objectives and first results

Abstract

We are presenting the design, technology development and tuning of the Single Photon Avalanche Diode fabricated on the germanium -silicon epitaxial layer. The ultimate goal is to develop a solid state photon detector with picosecond timing resolution and stability and an increased spectral sensitivity beyond 1100 nanometres in comparison to detectors based on silicon. The technology development steps on the Ge-Si epitaxial layer are presented together with the first results of the preparation of the shallow junction and its parameters. The diffusion and annealing models have been tuned for GeSi epitaxial layer and implantation. The resulting concentration profiles have been verified by two independent diagnostics methods. The first avalanche diode structures on the basis of the Ge0.4Si0.6, epitaxial layer on Silicon have been prepared and tested. The ability of the avalanche structure to operate in a Geiger mode has been demonstrated for the first time, the dark count rate has been measured. The serial resistance of the structure above its breakdown voltage has been measured. The detection sensitivity in the wavelength range of 500 to 1600 nanometres has been measured.