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Jafar Ghazanfarian

Zahra Shomali, Behrad Pedar, Jafar Ghazanfarian, Abbas Abbassi
Monte-Carlo Parallel Simulation of Phonon Transport for 3D Silicon Nano-Devices
شبیه سازی مونت کارلوبرای انتقال فونون در ساختار سیلیکونی نانو با پرازش موازی

Due to the importance of the transistors in nano-electronics technology, the accurate study of these nano-devices is an essential field of research. Taking into account the non-Fourier nature of heat transfer with considering the  three-dimensional structure of the silicon nano-devices, are the challenges in transistor analysis which have not been studied precisely yet. Using the Monte-Carlo method for solving the Boltzmann equation, two actual three-dimensional silicon transistors are accurately simulated. First, the accuracy of the method is verified by the investigation of heat transport in different regimes for a cuboid. Then, the procedure is used to simulate a 2-D silicon nano-device. The obtained results present good consistency with the existent data. Then, the 3-D silicon structure is investigated in two different cases with various boundary conditions, and the formation of the hot zone is announced. Farther, it is attained that a temperature-jump occurs around the time $t=22 ps$. This phenomena is attributed to the change of the type of the dominant heat carriers from acoustic phonons to the optical ones. Furthermore, it is found that although the transistor is still heated the peak temperature starts to decrease when time passes $t=200 ps$. Moreover, as the heat source is switched off at $t=500 ps$, the temperature is acquired to suffer many fluctuations until the expecting descending behaviour appears at $t=726 ps$. Such deportment takes place due to the imprisoning the existent heat in the hot-spot between the isolated boundaries. Besides, the results reveals that redesigning the transistors in case two by leaving the end parts of the top boundary which are in contact with the metallic material open, strengthens the presence of the hot-spot while fastening the heat release to the environment. Also the temperature profiles of the second case exhibits odd behaviours as well. Finally, it should be emphasized that this research compensates the lack of heat transfer data for the thermal investigation of 3-D MOS devices.



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