Thermal Penetration Depth Analysis and Impact of the BEOL Metals on the Thermal Impedance of SiGe HBTs

In this letter, we present a detailed investigation on how dynamic thermal phenomena take place in state of-the-art SiGe HBTs when excited by sinusoidal power dissipation. To give a better insight into the mechanisms leading to the thermal impedance (Zth) decay, we introduce the concept of thermal penetration depth; then, with the help of 3-D thermal simulations, we illustrate its effect on the sp...