The Impact of Surface Passivation on Kapitza Resistance at the Interface between a Semiconductor and Liquid Nitrogen

TL;DR

This study examines how silicon nitride passivation layers affect the Kapitza resistance at the interface between a semiconductor and liquid nitrogen, revealing that thicker passivation layers increase thermal boundary resistance.

Contribution

It provides experimental measurements of Kapitza resistance variations with SiN passivation thickness at cryogenic temperatures, highlighting the impact of surface passivation on thermal interface conductance.

Findings

Kapitza resistance increases with passivation thickness.

Thicker SiN layers impede heat transfer at cryogenic interfaces.

Surface passivation significantly influences thermal boundary resistance.

Abstract

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.