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[IEEE 2018 41st International Spring Seminar on Electronics Technology (ISSE) - Zlatibor, Serbia (2018.5.16-2018.5.20)] 2018 41st International Spring Seminar on Electronics Technology (ISSE) - Solid-Liquid Interdiffusion Bonding Based on Au-Sn Intermetallic for High Temperature Applications
摘要： This paper covers one of the aspects of solid-liquid interdiffusion (SLID) bonding of semiconductor structures to substrate for high temperature operation. Investigations were focused on Au/Sn intermetallic compounds formed at the interface between Au metallization on the chip and Sn metallization on the DBC (Direct Bonded Copper) substrate. Two version of SLID were applied: one stage process at 350?°C and two stage process short time at 280?°C + long time at 180?°C. Second process is divided into two steps: short high temperature (280?°C) step for melting Sn and initial intermetallic compound formation and long low temperature (180?°C) step for solid state diffusion process. Design of experiments technique was used for process optimization. The best process parameters were obtained and they were applied for monocrystalline GaN chips assembly to DBC substrates. In the long-term stability tests at 300?°C it was proven that both versions of investigated SLID technique can be applied for monocrystalline GaN chips assembly. Critical condition for this assembly operation is high enough pressure applied on the chip to initiate diffusion process.
关键词： High Temperature Applications,GaN chips,Au-Sn Intermetallic,DBC substrate,Solid-Liquid Interdiffusion Bonding
更新于2025-09-23 15:21:21
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Photonic materials for high-temperature applications: Synthesis and characterization by X-ray ptychographic tomography
摘要： Photonic materials for high-temperature applications need to withstand temperatures usually higher than 1000 ?C, whilst keeping their function. When exposed to high temperatures, such nanostructured materials are prone to detrimental morphological changes, however the structure evolution pathway of photonic materials and its correlation with the loss of material’s function is not yet fully understood. Here we use high-resolution ptychographic X-ray computed tomography (PXCT) and scanning electron microscopy (SEM) to investigate the structural changes in mullite inverse opal photonic crystals produced by a very-low-temperature (95 ?C) atomic layer deposition (ALD) super-cycle process. The 3D structural changes caused by the high-temperature exposure were quantified and associated with the distinct structural features of the ceramic photonic crystals. Other than observed in photonic crystals produced via powder colloidal suspensions or sol-gel infiltration, at high temperatures of 1400 ?C we detected a mass transport direction from the nano pores to the shells. We relate these different structure evolution pathways to the presence of hollow vertexes in our ALD-based inverse opal photonic crystals. Although the periodically ordered structure is distorted after sintering, the mullite inverse opal photonic crystal presents a photonic stopgap even after heat treatment at 1400 ?C for 100 h.
关键词： Ptychography X-ray computed tomography,High-temperature applications,3D image analysis,Photonic materials,Low-temperature atomic layer deposition
更新于2025-09-23 15:21:01
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Gallium Oxide || Ga2O3-based gas sensors
摘要： β-Ga2O3 has recently gained a lot of interest for applications in solar-blind deep ultraviolet (UV) detectors and high-power electronics at elevated temperatures. The interest stems from its intrinsic material properties, such as wide-bandgap nature (4.9 eV) and high breakdown electric field. β-Ga2O3 can also serve as a reactive oxide layer, sensitive to a wide variety of gases, especially at high temperatures in harsh environments. Many β-Ga2O3-based gas sensors have been reported recently [1–20]. In this chapter, the gas sensing mechanism and the sensing characteristics of β-Ga2O3 are reviewed. First, the material properties of β-Ga2O3 are reviewed for a clear understanding of surface reactions at oxide surfaces with various gas molecules. The crystal structure of β-Ga2O3 and the surface atomic configurations of 201 and (010)-oriented β-Ga2O3 are investigated. The wet and dry etching characteristics and the metal contact properties of 201 and (010) β-Ga2O3 single crystals are discussed for a broad range of device applications. Recent reports of β-Ga2O3-based hydrogen sensors are discussed, and the hydrogen sensing properties of 201 and (010) β-Ga2O3 single crystals are compared for enhanced hydrogen detection.
关键词： crystal structure,β-Ga2O3,high-temperature applications,wet and dry etching,Ohmic contact,gas sensors,hydrogen sensors
更新于2025-09-09 09:28:46