Cross-sectional scanning thermal microscopy of ErAs/GaAs superlattices grown by molecular beam epitaxy

Abstract

Scanning thermal microscopy has been implemented in a cross-sectional geometry, and its application for quantitative, nanoscale analysis of thermal conductivity is demonstrated in studies of an ErAs/GaAs nanocomposite superlattice. Spurious measurement effects, attributable to local thermal transport through air, were observed near large step edges, but could be eliminated by thermocompression bonding to an additional structure. Using this approach, bonding of an ErAs/GaAs superlattice grown on GaAs to a silicon-on-insulator wafer enabled thermal signals to be obtained simultaneously from Si, SiO 2 , GaAs, and ErAs/GaAs superlattice. When combined with numerical modeling, the thermal conductivity of the ErAs/GaAs superlattice measured using this approach was 11±4 W/m·K.

Quantifying thermal transport in buried semiconductor nanostructures via cross-sectional scanning thermal microscopy

“…[8][9][10] However, whilst using SThM to quantify the overall thermal conductance of the complex 3D structure remains challenging but possible, assessing thermal conductivities of the individual structure elements buried in the 3D device and reliably separating them from the interfacial thermal resistance remains out-of-reach of the technique. Several groups [11][12][13][14][15][16] devoted their studies to temperature and conductance measurements using SThM. While Park et al 13 reported measurements of ErAs/GaAs MBE superlattices with 6 nm RMS roughness, Juszczyk et al 14 used craters in photonic structures to access subsurface materials.…”

Improving accuracy of nanothermal measurements via spatially distributed scanning thermal microscope probes

“…Very significantly, its ability to perform relevant measurements of thermal transport in ambient conditions, that has been a limiting factor for other SThM probes 12 , render PdRPs as the mainstream probe for nanothermal characterization, they have been used extensively for a variety of applications from biological studies 13,14 to soft matter 15 and condensed matter sciences [16][17][18] .…”

Quantitative Mapping of Nanothermal Transport via Scanning Thermal Microscopy

“…Thin films on substrate [72][73][74] or even 2D materials [68,75,76] have been investigated. Complex structures can also be scanned as long as the surface is smooth enough to avoid dominance of topography-related artefacts [77][78][79].…”

“…Moreover, its main advantage is its ability to work in a range of conditions from vacuum [34,75] and air [49] to liquids [88]. Very significantly, its ability to perform relevant measurements of thermal transport in ambient conditions, that has been a limiting factor for other SThM probes [116], render PdRPs as the mainstream probe for nanothermal characterisation, they have been used extensively for a variety of applications from biological studies [117,118] to soft matter [119] and condensed matter sciences [78,120,121]. Here we also consider other experimental parameters which can influence SThM measurements during the experiment namely variations in sample temperature and microscope temperature, affecting the temperature of the base of the sensor (Fig.…”

“…However, accessing intrinsic and subsurface properties remains challenging. Several groups [77,78,[155][156][157] To address these challenges, we used a unique nano-sectioning tool using Arion beams impinging on the side of a sample at shallow angle (∼ 5 • ) and exiting through the sample surface, beam-exit cross-sectional polishing (BEXP) [158,159]. As we will explain in the following section, the thermal spreading resistance of a layer on a substrate is expected to increase (decrease) if the thermal conductivity of the layer is smaller (larger) than that of the substrate ( k layer k substrate < 1 or > 1).…”