Design of silicon hetero-interface photodetectors

Abstract

In a silicon hetero-interface photodetector, Si is used as the multiplication material to provide avalanche gain, while InGaAs is used as the absorption material. High quantum efficiency, high gain-bandwidth product, and low noise detection of wavelengths between 1.0 and 1.6 mm can be achieved in this way. We derive expressions for the frequency response for these detectors, present possible design variations, and analyze their performance. The effects of parasitics, transit time, and RC roll-off on frequency response are investigated and the 3-dB bandwidth and gain bandwidth product are calculated. Particular attention is paid to a 10 Gbit/s APD and we show that that a 3-dB bandwidth of 10 GHz and a gain-bandwidth product in excess of 400 GHz should be possible.

High Gain Effects for Solid-State Impact-Ionization Multipliers

“…2 is well above the field required for electrons and holes to travel with their saturation velocity. For comparable Si APDs with a 5-m-thick multiplication layer, the bandwidth is calculated to be around 2 GHz [17]. The measurement setup and test results for device speed will be discussed in future papers.…”

Atomic-plane-thick reconstruction across the interface during heteroepitaxial bonding of InP-clad quantum wells on silicon

“…[3][4][5][6] We propose that when optoelectronic devices are concerned, oxide-free bonding should be preferred since it is reported to demonstrate advantageous electrical interface quality compared to oxide mediated bonding. 7 Efficient electrical properties have been demonstrated for InGaAs bulk layers oxide-free bonded on Si in the case of silicon-based avalanche photodiodes 8,9 some times ago, or much more recently in the case of InAs/GaAs quantum dot lasers on Si. 10,11 When investigating advanced optical designs, it is also preferable to avoid any connex or continuous low-opticalindex amorphous layer of poor thermal conductivity in the core of the guiding layers formed by the two bonded materials.…”