M. Seto

Silicon-based resonant-cavity-enchanced photodiode with a buried SiO2 reflector

We report on a silicon-based resonant cavity photodiode with a buried silicon dioxide layer as the bottom reflector. The buried oxide is created by using a separation by implantation of oxygen technique. The device shows large Fabry–Perot oscillations. Resonant peaks and antiresonant troughs are observed as a function of the wavelength, with a peak responsivity of about 50 mA/W at 650 and 709 nm. The leakage current density is 85 pA/mm2 at −5 V, and the average zero-bias capacitance is 12 pF/mm2. We also demonstrate that the buried oxide prevents carriers generated deep within the substrate from reaching the top contacts, thus removing any slow carrier diffusion tail from the impulse response.

PERFORMANCE DEPENDENCE OF LARGE-AREA SILICON p-i-n PHOTODETECTORS UPON EPITAXIAL THICKNESS

Abstract Large-area silicon p - i - n photodetectors with an epitaxial thickness ranging from 10–20 μm were fabricated. The photodiode bandwidth, responsivity, capacitance and dark current were characterized as a function of the epilayer thickness. The determination of these parameters is important to facilitate the designing of photodiodes in which the trade-off between various parameters need to be known, and in aiding its integration with other devices where the epitaxial requirements can be quite different.

Low-leakage-current metal–insulator–semiconductor–insulator–metal photodetector on silicon with a SiO2 barrier-enhancement layer

We show that the leakage current through a metal–semiconductor–metal photodetector can be reduced by placing a thin interfacial silicon dioxide layer between the Schottky metal and the silicon substrate. We measure a factor 5.2 reduction in leakage-current density to 18 μA/cm2 at 5 V, a weaker increase in dark current with bias, and a factor 3.5 improvement in photoresponsivity to 0.39 A/W. We do not observe any noticeable reduction in device speed using this interfacial oxide.

Si/SiGe resonant-cavity photodiodes for optical storage applications

We report on a resonant cavity photodiode with a Si/SiGe Bragg mirror grown by low temperature chemical vapor deposition suitable for short wavelength detection around 600–700 nm. The presence of Fabry-Perot oscillations in the spectral response of the photodiode are indicative of its wavelength selectivity.

Leakage current reduction of metal-semiconductor-metal photodetectors by using a thin interfacial silicon dioxide layer

In this report, we show that a thin interfacial silicon dioxide layer placed between the Schottky metal and the silicon substrate reduces the leakage current of a metal- semiconductor-metal photodetector. We find the optimal interfacial oxide layer to be about 3 or 4 nm thick and is made by dry furnace oxidation of the silicon substrate at 800 degrees Celsius, taken from a 0.18 micrometer CMOS process normally used to make the gate oxide. As compared to a metal- semiconductor-metal detector without this oxide layer, we measure a factor 5 reduction in leakage current density to 18 (mu) A/cm2 at 5 V, a weaker increase in dark current with bias, and a factor 3 improvement in photoresponsivity to 0.35 A/W at 635 nm wavelength. Additionally, we compare Schottky barrier height, effective Richardson constant, and capacitance measurements between photodetectors made with and without this interfacial oxide.

Silicon-on-insulator resonant cavity photodiode without a slow carrier diffusion tail

We report on a novel silicon-based resonant cavity photodiode with a buried silicon dioxide layer as the bottom reflector. The buried oxide is created by using a separation by implantation of oxygen technique. The device shows large Fabry-Perot oscillations. Resonant peaks and anti-resonant troughs are observed as a function of the wavelength, with a peak responsivity of about 50 mA/W at 650 nm and 709 nm. The leakage current density is 85 pA/mm2 at -5 V, and the average zero-bias capacitance is 12 pF/mm2. We also demonstrate that the buried oxide prevents carriers generated deep within the substrate from reaching the top contacts, thus removing any slow carrier diffusion tail from the impulse response.