Cooling electronic devices to cryogenic temperatures (< 77 K) is crucial in
various scientific and engineering domains. Efficient cooling involves the
removal of heat generated from these devices through thermal contact with
either a liquid cryogen or a dry cryostat cold stage. However, as these devices
cool, thermal boundary resistance, also known as Kapitza resistance, hinders
the heat flow across thermal interfaces, resulting in elevated device
temperatures. In transistors, the presence of passivation layers like Silicon
Nitride (SiN) introduces additional interfaces that further impede heat
dissipation. This paper investigates the impact of passivation layer thickness
on Kapitza resistance at the interface between a solid device and liquid
nitrogen. The Kapitza resistance is measured using a capacitance thermometer
that has been passivated with SiN layers ranging from 0 to 240 nm. We observe
that Kapitza resistance increases with increasing passivation thickness.Comment: 6 pages, 5 Figure