The need for increased control of layer thickness and uniformity as device dimensions shrink has spurred increased use of atomic layer deposition (ALD) for thin film growth. The ability to deposit high dielectric constant (high-k) films via ALD has allowed for their widespread use in a swath of optical, optoelectronic, and electronic devices, including integration into CMOS compatible platforms. As the thickness of these dielectric layers is reduced, the interfacial thermal resistance can dictate the overall thermal resistance of the material stack compared to the resistance due to the finite dielectric layer thickness. Time domain thermoreflectance is used to interrogate both the thermal conductivity and the thermal boundary resistance of aluminum oxide, hafnium oxide, and titanium oxide films on silicon. We calculate a representative design map of effective thermal resistances, including those of the dielectric layers and boundary resistances, as a function of dielectric layer thickness, which will be of great importance in predicting the thermal resistances of current and future devices.

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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.

Germanium–antimony–telluride has emerged as a nonvolatile phase change memory material due to the large resistivity contrast between amorphous and crystalline states, rapid crystallization, and cyclic endurance. Improving thermal phase stability, however, has necessitated further alloying with optional addition of a quaternary species (e.g., C). Here, the thermal transport implications of this additional species are investigated using frequency-domain thermoreflectance in combination with structural characterization derived from x-ray diffraction and Raman spectroscopy. Specifically, the room temperature thermal conductivity and heat capacity of (Ge2Sb2Te5)1−xCx are reported as a function of carbon concentration (x≤0.12) and anneal temperature (T≤350°C) with results assessed in reference to the measured phase, structure, and electronic resistivity. Phase stability imparted by the carbon comes with comparatively low thermal penalty as materials exhibiting similar levels of crystallinity have comparable thermal conductivity despite the addition of carbon. The additional thermal stability provided by the carbon does, however, necessitate higher anneal temperatures to achieve similar levels of structural order.

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Nanomultilayers are complex architectures of materials stacked in sequence with layer thicknesses in the nanometer range. Their application in microelectronics is challenged by their thermal stability, conductivity and interface reactivity which can compromise their performance and usability. By using different materials as thermal barriers and by changing their thickness, it is possible to manipulate interfacial effects on thermal transport. In this work, we report on the thermal conductivity of Cu/W, Cu/Ta, and Cu/TaN sputter deposited nanomultilayers with different thicknesses. The resistive interfacial effects are rationalized and discussed also in relation to the structural transformation into a nano-composite upon high temperature annealing.

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Studies of size effects on thermal conductivity typically necessitate the fabrication of a comprehensive film thickness series. In this Letter, we demonstrate how material fabricated in a wedged geometry can enable similar, yet higher-throughput measurements to accelerate experimental analysis. Frequency domain thermoreflectance (FDTR) is used to simultaneously determine the thermal conductivity and thickness of a wedged silicon film for thicknesses between 100 nm and 17 μm by considering these features as fitting parameters in a thermal model. FDTR-deduced thicknesses are compared to values obtained from cross-sectional scanning electron microscopy, and corresponding thermal conductivity measurements are compared against several thickness-dependent analytical models based upon solutions to the Boltzmann transport equation. Our results demonstrate how the insight gained from a series of thin films can be obtained via fabrication of a single sample.