Contactless Thermometry Research Articles

Extraction of interfacial thermal resistance across organic/semiconductor interface using optical-interference contactless thermometry

Abstract We have developed an experimental method to extract interfacial thermal resistance (ITR) at organic/semiconductor interface based on optical-interference contactless thermometry. The proposed technique was applied to the SU-8/SiC bilayer sample, and clear oscillations in reflectivity induced by optical interference during pulse heating and cooling were observed. Measured ITR increased with the temperature of SU-8 around interface from 170 mm2KW-1 at 304 K to 515 mm2KW-1 at 369 K. The increasing ITR also leads to an increase in the temperature drop at the interface from 7 K to 73 K.

Development of a real-time temperature measurement technique for SiC wafer during ultra-rapid thermal annealing based on optical-interference contactless thermometry (OICT)

A real-time temperature measurement technique with high spatial (≤20 μm) and temporal (≤1 μs) resolutions for SiC wafers during ultra-rapid thermal annealing (URTA) has been developed based on optical-interference contactless thermometry (OICT). This technique consists of hardware (OICT imaging setup) and software (fast temperature extraction program). Under URTA by atmospheric-pressure thermal plasma jet, a clear variation of optical-interference fringes was observed by a high-speed camera and then analyzed by a fast temperature extraction program using image preprocessing and a database. 3.5D (x, y, z and time) temperature distribution in SiC wafer was obtained within 0.43 s.

Direct observation of three-dimensional transient temperature distribution in SiC Schottky barrier diode under operation by optical-interference contactless thermometry imaging

We have developed optical-interference contactless thermometry imaging technique to visualize three-dimensional transient temperature distribution in 4H-SiC Schottky barrier diode (SBD) under operation. When a 1 ms forward pulse bias was applied, clear variation of optical interference fringes induced by self-heating and cooling were observed. Thermal diffusion and optical analysis revealed three-dimensional temperature distribution with high spatial (≤10 μm) and temporal (≤100 μs) resolutions. A hot spot that signals breakdown of the SBD was successfully captured as an anomalous interference, which indicated a local heating to a temperature as high as 805 K at the time of failure.

Upconverting NIR-to-NIR LuVO4:Nd3+/Yb3+ Nanophosphors for High-Sensitivity Optical Thermometry.

Accurate contactless thermometry is required in many rapidly developing modern applications such as biomedicine, micro- and nanoelectronics, and integrated optics. Ratiometric luminescence thermal sensing attracts a lot of attention due to its robustness toward systematic errors. Herein, a phonon-assisted upconversion in LuVO4:Nd3+/Yb3+ nanophosphors was successfully applied for temperature measurements within the 323-873 K range via the luminescence intensity ratio technique. Dual-activating samples were obtained by codoping and mixing single-doped nanopowders. The effect of the type of dispersion system and the Yb3+ doping concentration was studied in terms of thermometric performances. The relative thermal sensitivity reached a value of 2.6% K-1, while the best temperature resolution was 0.2 K. The presented findings show the way to enhance the thermometric characteristics of contactless optical sensors.

(Invited) Millisecond Annealing by Atmospheric Pressure Thermal Plasma Jet and Direct Imaging of Temperature Distribution Using Optical Interference Contactless Thermometry (OICT)

A non-contact temperature measurement technique on the basis of optical interference has been developed [1,2]. In Optical Interference Contactless Thermometry (OICT), the transient reflectivity of a substrate during rapid annealing is measured and reproduced by thermal simulation and optical analysis, whereupon the temperature profile is obtained from the simulation results. This method allows us to obtain a temperature distribution inside the wafer because it has depth resolution, unlike other interferometric methods. The time resolution of OICT is dependent on the photodetector, therefore, a millisecond detection of temperature variation is possible. By introducing a proper probe laser, this method can be applied to various substrates such as silicon, silicon carbide, glass, and so on [3-5]. OICT is useful to monitor transient temperature variation during rapid thermal processing. This helps us to correlate the annealing history to the characteristics of annealed samples. For instance, we have demonstrated the direct measurement of crystallization temperature of amorphous silicon, the role of heating and cooling speed on the yield of impurity activation in shallow junction, and the densification of gate SiO2 films and its effect on reliability of transistors under operation [6-9]. In this study, OICT has been extended to temperature field imaging. The principle is the same, and a high-speed camera replaced the photodetector to capture the 2-dimensional interference contour images. The images are analyzed to transfer them to temperature distributions. In the experiment, semiconductor wafers were annealed by atmospheric-pressure thermal plasma jet (TPJ) and the optical measurement was performed from the backside of the wafers. Probe lasers with the wavelengths of 1310nm for silicon wafers, and 633nm for silicon carbide wafers, were used. The laser lights went through a beam expander and irradiated the samples via a beam splitter and the reflected lights were introduce to high-speed cameras. Clear contour movies were obtained, where the contour lines correspond to isothermal lines. This temperature imaging method enables fast analysis of temperature, which can be used for the feedback to the annealing conditions as the real-time monitoring technique.[1] T. Okada, Jpn. J. Appl. Phys., 45 (2006) 4355.[2] T. Okada, Thin Solid Films, 515 (2007) 4897.[3] H. Furukawa, ECS Trans., 13 (1) (2008) 31.[4] K. Maruyama, Jpn. J. Appl. Phys., 54 (2015) 06GC01-1.[5] A. Kameda, J. Appl. Phys., 127 (2020) 203302-1.[6] Y. Mizukawa, Appl. Phys. Express, 13 (2020) 015507-1.[7] K. Matsumoto, Jpn. J. Appl. Phys., 49 (2010) 04DA02-1.[8] K. Matsumoto, Jpn. J. Appl. Phys., 50 (2011) 04DA07-1.[9] S. Higashi, Jpn. J. Appl. Phys., 50 (2011) 03CB10-1.

(Invited) Millisecond Annealing by Atmospheric Pressure Thermal Plasma Jet and Direct Imaging of Temperature Distribution Using Optical Interference Contactless Thermometry (OICT)

Ultra-rapid thermal annealing in millisecond has been performed by atmospheric-pressure thermal plasma jet (TPJ) and temperature measurement based on optical interference contactless thermometry (OICT) is investigated. On the basis of optical interference in silicon wafer induced by the change in refractive index and its analysis, transient temperature variation is obtained with millisecond time resolution. Moreover, OICT imaging allow us to obtain the temperature information in planar and depth direction simultaneously.

Energy transfer in Tb3+- Yb3+ doubly doped CsGd(MoO4)2 single crystals for contactless thermometry, solid-state lighting and solar cells

ABSTRACT A novel terbium (Tb3+) and ytterbium (Yb3+) co-doped optical quality CsGd(MoO4)2 single crystals were grown by the low-thermal-gradient Czochralski method. Photoluminescence spectra were measured and studied for Tb3+– Yb3+ doubly doped CsGd(MoO4)2 crystals at 77–340 K temperature range. Under 330 nm excitation the main peaks of Tb3+ and Yb3+ emission were observed. Decay curves were obtained for the energy levels 5D4 of Tb3+ and 2F7/2 of Yb3+ in CsGd(MoO4)2 crystals. Decay time for Tb3+ transitions significantly varies at temperatures close to ambient. Such behaviour allows to assume perspective application of this effect for non-contact luminescence lifetime thermometry. The emission colour chromaticity coordinates of CsGd(MoO4)2: Tb3+ -Yb3+ crystals are close to SMPTE (Society of Motion Picture and Television Engineers) standard for green colour, as shown on CIE 1931 diagram. Correlated colour temperature varies from 5538 K at 77 K to 4297 K at 340 K.

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials.

SummaryControl of temperature variation is of primordial importance in particular areas of biomedicine. In this context, medical treatments such as hyperthermia and cryotherapy, and also the development and use of hydrogel-based biomaterials, are of particular concern. To enable accurate temperature measurement without perturbing or even destroying the biological tissue or material to be monitored, contactless thermometry methods are preferred. Among these, the most suitable are based on magnetic resonance imaging and spectroscopy (MRI, MRS). Here, we address the latest developments in this field as well as their current and anticipated practical applications. We highlight recent progress aimed at rendering MR thermometry faster and more reproducible, versatile, and sophisticated and provide our perspective on how these new techniques broaden the range of applications in medical treatments and biomaterial development by enabling insight into finer details of thermal behavior. Thus, these methods facilitate optimization of clinical and industrial heating and cooling protocols.

Combined Application of Dual-Wavelength Fluorescence Monitoring and Contactless Thermometry during Photodynamic Therapy of Basal Cell Skin Cancer.

The aim of the study was to assess the capabilities of combined application of dual-wavelength fluorescence visualization and contactless skin thermometry during photodynamic therapy monitoring (PDT) of basal cell cancer.Materials and Methods.The study was performed at the University Clinic of Privolzhsky Research Medical University (Nizhny Novgorod). Nine clinically, dermatoscopically, and histologically verified foci of basal cell skin cancer were exposed to PDT sessions (wavelength of 662 nm, light dose density of 150 J/cm2) with systemic application of chlorin-based photosensitizer Fotoditazin. A semiconductor laser system Latus-T (Russia) was employed for irradiation. Dual-wavelength fluorescence visualization and contactless thermometry with an IR pyrometer were used to monitor the PDT sessions.Results.The PDT sessions of nine foci of basal cell cancer were carried out under the control of fluorescence imaging and contactless thermometry. Photosensitizer photobleaching in all foci amounted to 40% signifying a percent of photosensitizer involved in the photodynamic reaction. It has been shown that the combined employment of dual-wavelength fluorescence monitoring and contactless thermometry during the PDT of basal cell skin cancer allows oncologists to control simultaneously the degree of photosensitizer photobleaching and the depth of the photodynamic effect in tissues, the extent of involving the mechanisms associated with hyperthermia as well as the correctness of the procedure conducting. In the course of 9-month dynamic follow-up after the treatment, no clinical and dermatoscopic signs of recurrence were found.Conclusion.A bimodal control of PDT enables the assessment of the correctness and efficacy of the procedure performance. The contactless control of tissue heating allows ensuring the temperature mode for hyperthermia realization, while the fluorescence monitoring makes it possible to evaluate the accumulation of the photosensitizer in the tumor and the depth of the PDT action as well as to predict the procedure efficacy based on the photobleaching data. The complementary use of these techniques allows the adjustment of the mode directly in the course of the PDT procedure. The acquisition of the sufficient statistical data on the combined monitoring will result in the development of a novel PDT protocol.

Support for the Uniformity of Measurements in the Area of Contactless Thermometry

Approaches to the development of methods for contactless thermometry are discussed on the basis of studies carried out over the time the primary standard of Ukraine DETU 06-03-96 has been in operation.

Rapid contactless thermometry with submilli-Kelvin resolution

We present a contactless method of detecting small changes in the surface temperature of metallic samples over a short time period. The thermometry method incorporates a contactless heater and simplifies sample preparation requirements for calorimetric measurements. We demonstrate that we can measure small temperature shifts (250μK) in 5ms at midrange temperatures (155K). This method does not serve as a conventional thermometer but as an in situ thermometer useful for narrow temperature ranges, such as the region of a phase transition (often exploited in bolometers). The manganite material Nd0.5Sr0.5MnO3 was chosen as a test material for our experiments because it is a well characterized material where resistivity and magnetization [Kuwakara et al., Science 270, 961 (1995)] and thermal conductivity [Kim et al., American Physical Society March Meeting, W24.009 (2004)] have been previously measured and the material undergoes a metal-insulator transition.

Heat Transfer Properties of Polymer Target Shells at Temperatures Between 250K and 350K

The emissivities and accommodation coefficients for helium and deuterium gas were measured for polystyrene target shells from several production batches. The shells varied in wall thickness, diameter and surface conditions as viewed with an optical microscope. For emissivity measurements, it is desirable for the radiative heat transfer to dominate over conductive heat transfer via the surrounding gas and the sample (and thermometer) mount. This is achieved by maintaining very low gas pressure (free molecular conduction regime) and by a novel contact-less thermometric measurement, in which the temperature of the shell is determined from the strongly temperature-dependent shell outgassing rate. The accommodation coefficient is also obtained in the process. Emissivity and accommodation coefficient results are reported in the temperature range 250 – 350K. The values are very low, in the 0.01 range for the former, and 0.003 range for the latter, which augurs well for thermal stability after the shroud removal prior to a target shot. For measurements at lower temperatures (down to 4K), other contact-less thermometry methods are proposed, with electronic magnetic susceptibility shown to be very favorable.

Classification and terminology in the field of contactless thermometry

Classification and terminology in the field of contactless thermometry