Ruxandra Costescu Erica Saltzman

Molecular Dynamics Simulation of Thermal Conduction over Silicon-Germanium Interface

• Ruxandra Costescu

• Erica Saltzman

• Zhi Tang

Purpose

• Thermal conductivity ()  a measure of thermal transport

•  behavior across interfaces is little-understood and drastically different from bulk behavior; interface thermal conductance (C) is significant for ultra-thin films (~100 nm).

• Si and Ge are important to semiconductor and microelectronics industries

Previous Research

Geometry

Boundary Conditions

• Periodic in lateral dimensions

• Hard-wall in longitudinal dimension

Temperature Regulations

• Initial conditions: hot, cold, and intermediate temperatures

• Velocity rescaling in hot and cold reservoirs

Tersoff Potential

Calculations

Results

• At 120 K

Results

• Thermal conductivity

Results

• Interface conductance results

Results

• Si+Ge(MD) smaller than eq as expected and the right order of magnitude; but dependence on temperature unclear

• DMM prediction of ~108 W/(m2 K) at 80 K reasonably close to calculated range of CSi/Ge

• Our values range from ~ 2 - 5  107 W/(m2 K)  the right order of magnitude of C

• Preliminary calculation for opposite direction of temp. gradient shows drastically different behavior (approximations fail?)

Results

• Fe (“fictitious force”)

• quantum correction

• direction of temperature gradient

• interface geometry

• compare t.c. results to exactly equivalent experimental data

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