Study of the Photo- and Thermoactivation Mechanisms in Nanoscale SOI Modulator

Abstract

A new nanoscale silicon-based modulator has been investigated at different temperatures. In addition to these two advantages, nanoscale dimensions (versus MEMS temperature sensors) and integrated silicon-based material (versus polymers), the third novelty of such optoelectronic device is that it can be activated as a Silicon-On-Insulator Photoactivated Modulator (SOIPAM) or as a Silicon-On-Insulator Thermoactivated Modulator (SOITAM). In this work, static and time dependent temperature effects on the current have been investigated. The aim of the time dependent temperature simulation was to set a temporal pulse and to check, for given dimensions, how much time would it take for the temperature profile and for the change in the electrons’ concentration to come back to the steady state. Assuring that the thermal response is fast enough, the device can be operated as a modulator via thermal stimulation or, on the other hand, can be used as thermal sensor/imager. We present here the design, simulation, and model of the second generation which seems capable of speeding up the processing capabilities. This novel device can serve as a building block towards the development of optical/thermal data processing while breaking through the way to all optic processors based on silicon chips that are fabricated via typical microelectronics fabrication process.

Small Signals’ Study of Thermal Induced Current in Nanoscale SOI Sensor

“…In previous work [29] a large signal analysis was made of the SOITAM photodetector's thermal properties. We continue this analysis here considering both an analytic model and numerical simulations.…”

“…Using the explicit temperature dependence of the current [29], we can next model the time variation of the current. In particular we may model the time response to the temperature perturbation in the simulation.…”

“…However, for temperature variations of sufficiently small amplitude, the response of the current in the channel will be essentially linear. Even for relatively large amplitudes, however, the near-linearity of the temperature dependence found in [29] means that the equivalent circuit description will be accurate, and the response of the channel current ought to show little distortion of the input temperature signal. The equivalent circuit model is thus expected to be useful for the small signal analysis as well.…”

“…The study of the large scale signal response was performed in [29]. For the small signal analysis the right hand side of (8) is given by…”

“…Indeed, several types of material and size [14,15] of siliconbased/CMOS nanoscale thermal sensors become much more desirable for integration in microelectronics circuitry [16][17][18][19][20][21][22][23][24][25][26][27][28]. So, in our previous work [29] we presented a dualmode device: Silicon-On-Insulator Photo-Activated Modulator (SOIPAM) combined with Silicon-On-Insulator ThermoActivated Modulator (SOITAM). The analysis focused on 2 Journal of Sensors large signals of the SOITAM photodetector's thermal properties.…”