Self heating in Si0.5Ge0.5/Si and GaAs/Si thin film device structures

• Si0.5Ge0.5 and GaAs films were grown on Si substrates by MBE.
• The interface thermal conductance between Si0.5Ge0.5 or GaAs film and Si is determined.
• The interface thermal conductance between Si0.5Ge0.5 and Si is found to be five times that between GaAs and Si.

Si0.5Ge0.5 and GaAs films grown on Si substrates were used to measure the interface thermal conductance between the films and the substrate. Transient thermoreflectance technique was used with the one-dimensional heat equation to simulate the experimental results. The results showed that the interface thermal conductance of SiGe/Si interface is 100 MW m−2 K−1 and that of GaAs/Si is 20 MW m−2 K−1. These values of interface thermal conductance combined with the thermal conductivity of the films were used to conclude that SiGe films are less susceptible to self heating than GaAs films of same thickness.