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Oxidized Metal Schottky Contacts on (010) β-Ga2 O 3
摘要： Oxidized Ir, Pd, Pt, Ag, and Au Schottky contacts (SCs) were fabricated on (010) β-Ga2O3 single crystal substrates via reactive rf sputtering using an O2:Ar plasma. The use of in-situ oxidizing conditions resulted in SCs with very high rectifying barriers in excess of 2.0 eV for all the metals investigated, representing an increase of 0.4 to 0.9 eV compared to the corresponding plain metal versions. Both the plain and oxidized metal SCs showed evidence of Fermi Level pinning with their laterally homogeneous barrier heights lying in narrow ranges of ~1.3 to 1.5 eV and ~2.2 to 2.4 eV, respectively, with little correlation with metal work function. This was attributed to the influence of metal-induced oxygen vacancies and gap states at the SC interface, respectively. The very high barriers of the oxidized SCs resulted in excellent high temperature performance with ~10 orders of magnitude of rectification at 180 oC, indicating the potential of this technique for the fabrication of high temperature unipolar devices.
关键词： Metal Induced Gap States,Fermi Level Pinning,Oxygen Vacancies,Semiconductor Interfaces,Schottky Diodes
更新于2025-09-23 15:22:29
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An Electrical Analysis of a Metal-Interlayer-Semiconductor Structure on High-Quality Si <sub/> 1? <i>x</i> </sub> Ge <sub/><i>x</i> </sub> Films for Non-Alloyed Ohmic Contact
摘要： In this paper, we have investigated the effect of a metal-interlayer-semiconductor (MIS) structure on intrinsic silicon-germanium (SiGe) film which is epitaxially grown by ultra-high vacuum chemical vapor deposition (UHV-CVD). Ultra-thin dielectric materials can alleviate Fermi-level pinning at the metal/Si1?xGex contact region by preventing penetration into the Si1?xGex of metal-induced gap states (MIGS) from the metal surface. The electrical properties which are the back-to-back current density and specific contact resistivity of the Ti/TiO2/Si1?xGex structure improve at the TiO2 interlayer thickness of 0.5 nm for all kinds of Si1?xGex film with various levels of germanium (Ge) concentration. The case of Si0.7Ge0.3 film, the specific contact resistivity of a Ti/TiO2(0.5 nm)/Si0.7Ge0.3 structure is reduced 80-fold compared to that of a Ti/Si0.7Ge0.3 structure. The effect of the MIS structure has been well demonstrated on Si1?xGex film, and as a result this structure is suggested as a novel source/drain (S/D) contact scheme for advanced Si1?xGex complementary metal-oxide-semiconductor (CMOS) technology.
关键词： Epitaxial Growth,Metal-Interlayer-Semiconductor,Source/Drain Contact,Silicon-Germanium,Fermi-Level Pinning,Specific Contact Resistivity
更新于2025-09-23 15:22:29
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Mechanical stress dependence of the Fermi level pinning on an oxidized silicon surface
摘要： A combination of micro-Raman spectroscopy and micro-XPS (X-ray photo-electron spectroscopy) mapping on statically deflected p-type silicon cantilevers is used to study the mechanical stress dependence of the Fermi level pinning at an oxidized silicon (001) surface. With uniaxial compressive and tensile stress applied parallel to the ?110? crystal direction, the observations are relevant to the electronic properties of strain-silicon nano-devices with large surface-to-volume ratios such as nanowires and nanomembranes. The surface Fermi level pinning is found to be even in applied stress, a fact that may be related to the symmetry of the Pb0 silicon/oxide interface defects. For stresses up to 240 MPa, an increase in the pinning energy of 0.16 meV/MPa is observed for compressive stress, while for tensile stress it increases by 0.11 meV/MPa. Using the bulk, valence band deformation potentials the reduction in surface band bending in compression (0.09 meV/MPa) and in tension (0.13 meV/MPa) can be estimated.
关键词： Mechanical stress,Raman spectroscopy,X-ray photoelectron spectroscopy,Surface Fermi level pinning,Silicon,Interface defect
更新于2025-09-19 17:15:36
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Evidence for Primal sp <sup>2</sup> Defects at the Diamond Surface: Candidates for Electron Trapping and Noise Sources
摘要： Many advanced applications of diamond materials are now being limited by unknown surface defects, including in the fields of high power/frequency electronics and quantum computing and quantum sensing. Of acute interest to diamond researchers worldwide is the loss of quantum coherence in near-surface nitrogen-vacancy (NV) centers and the generation of associated magnetic noise at the diamond surface. Here for the first time is presented the observation of a family of primal diamond surface defects, which is suggested as the leading cause of band-bending and Fermi-pinning phenomena in diamond devices. A combination of density functional theory and synchrotron-based X-ray absorption spectroscopy is used to show that these defects introduce low-lying electronic trap states. The effect of these states is modeled on band-bending into the diamond bulk and it is shown that the properties of the important NV defect centers are affected by these defects. Due to the paramount importance of near-surface NV center properties in a growing number of fields, the density of these defects is further quantified at the surface of a variety of differently-treated device surfaces, consistent with best-practice processing techniques in the literature. The identification and characterization of these defects has wide-ranging implications for diamond devices across many fields.
关键词： surfaces,Fermi-level pinning,defects,diamond,NEXAFS
更新于2025-09-10 09:29:36
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First Experimental Demonstration and Mechanism of Abnormal Palladium Diffusion Induced by Excess Interstitial Ge
摘要： This letter represents the ?rst direct experimental demonstrations and mechanism proposal regarding abnormal palladium diffusion into germanium (Ge). Our experiments indicated that excess Ge atoms among palladium germanide alloy formation indirectly induce the abnormal out-diffusion of mass palladium atoms into Ge. Consequently, palladium germanide alloy on both n-type and p-type Ge form ohmic-like Schottky junctions. To identify this phenomenon, ?rst-principle calculations and technology computer-aided design simulation were used to evaluate the electrical in?uence of palladium atoms in Ge. We discovered that the activated palladium atoms in Ge induce large midgap bulk-trap states, which contribute to a severe increment of trap-assisted tunneling current at the palladium germanide/Ge junction.
关键词： Schottky junction,First-principles calculations,palladium germanide,technology computer-aided design,germanium,trap-assisted tunneling,fermi-level pinning effect
更新于2025-09-10 09:29:36