Thermal resistance and heat capacity in hafnium zirconium oxide (Hf1–xZrxO2) dielectrics and ferroelectric thin films

Abstract

We report on the thermal resistances of thin films (20 nm) of hafnium zirconium oxide (Hf 1-x Zr x O 2) with compositions ranging from 0 x 1. Measurements were made via timedomain thermoreflectance and analyzed to determine the effective thermal resistance of the films in addition to their associated thermal boundary resistances. We find effective thermal resistances ranging from 28.79 to 24.72 m 2 K GW À1 for amorphous films, which decreased to 15.81 m 2 K GW À1 upon crystallization. Furthermore, we analyze the heat capacity for two compositions, x ¼ 0.5 and x ¼ 0.7, of Hf 1-x Zr x O 2 and find them to be 2.18 6 0.56 and 2.64 6 0.53 MJ m À3 K À1 , respectively.

First-principles study of thermal transport properties in ferroelectric HfO2 and related fluorite-structure ferroelectrics

“…The low room-temperature k L (3.9 W m −1 K −1 ) in thin-film ferroelectric Hf 0.5 Zr 0.5 O 2 is further suppressed by the boundary scattering. For example, the calculated room-temperature effective thermal conductivity κ eff at a film thickness L of 20 nm is 1.8 W m −1 K −1 , in reasonable agreement with the experimentally measured value of 1.1 W m −1 K −1 for Hf 0.58 Zr 0.42 O 2 of the same L 36 and comparable to that of the conventional lead zirconate-titanate (PZT) solid solutions at a larger L ( e.g. , the κ eff in PZT is 1.2–2.2 W m −1 K −1 at a L of 95 nm).…”

“…Moreover, the size effect comes into play as ferroelectric Hf 1− x Zr x O 2 solid solution is typically tens of nanometers thick, whereas k in the thin film is further suppressed by the boundary scattering of phonons. 35 These pose a serious challenge for the thermal conduction of Hf 1− x Zr x O 2 solid solution, as the experimental measurement for thin-film Hf 1− x Zr x O 2 solid solution 36 yields a much lower k than the theoretical value of ferroelectric HfO 2 , 22 and hence a detailed understanding of the impacts of mass disorder and size effect is highly desired.…”

Laser-induced contamination deposit growth mechanisms on space optics

“…For another cross check, we used a heat capacity value of Cv=2.7 MJ/(m3 K) (Ref. 25) for the hafnia layer and the known physical film thickness of 244 nm to calculate that 43 ppm of the light should be absorbed to obtain a temperature rise of 257 K at a fluence of 0.39 J/cm2. The calculated value of 43 ppm is very close to the absorption measured on similar layers by the manufacturers of our substrates 22 …”

Thermal conductivity of yttria‐stabilized zirconia thin films grown by plasma‐enhanced atomic layer deposition

“…Instead, applying a series resistor model, TDTR determines the effective thermal conductivity (𝑘 ef f ) that includes contributions from the YSZ layer and its front side and back side interfaces: 𝑑 YSZ ∕𝑘 ef f = 1∕𝐺 Al∕YSZ + 𝑑 YSZ ∕𝑘 YSZ + 1∕𝐺 YSZ∕Si, where 𝑑 YSZ is the thickness of the YSZ layer. 26,[32][33][34][35][36][37] All the other parameters, except the above three, in the multilayer thermal model are either taken from literature or measured independently. These include the thickness, thermal conductivity, and volumetric heat capacity of the Al transducer layer (𝑑 Al , 𝑘 Al , 𝐶 Al ), the thickness and volumetric heat capacity of the YSZ layer (𝑑 YSZ , 𝐶 YSZ ), and the thermal conductivity and volumetric heat capacity of the Si substrate (𝑘 Si , 𝐶 Si ).…”