Recent commercialization has increased the research interest in transparent conducting oxides like indium tin oxide being implemented in display technologies and sensors. A wide range of values (4.2-5 eV) for the work function of ITO films are reported in literature. In this paper, we present an approach to extract the work function of indium tin oxide films from MOSFET devices. RF sputtered indium tin oxide is used as a transparent gate electrode to fabricate n-MOSFET. For the fabrication of the MOSFET, a four-level mask is used. Electrical characterization is performed on these MOSFET devices. We obtained work function value in the range between 4.62-4.81 eV using this technique. © The Author Indium tin oxide (ITO) is highly conductive wide bandgap semiconductor and exhibits excellent light transmission characteristics in visible and infrared spectrum. 1 The high electrical conductivity is due to contribution of oxygen vacancies and substitutional tin (Sn). Due to these unique properties, they are used as passive elements such as transparent electrodes in light-emitting devices (LED), 2 solar cells 3 and liquid crystal displays. 4 ITO is also used in organic electroluminescent devices like organic-LED (OLED) as an anode or a hole-injecting electrode due to its characteristic high work function ( ). 5 The work function of ITO also plays a central role in determining the efficiency and performance of the OLEDs and organic photovoltaics (OPVs) through control of hole injection process. 6,7 ITO is commonly regarded as high work function electrode. In the past, ITO has been used as hole collecting electrode in OPVs, or hole injecting electrode in OLEDs. Currently, OPVs or OLEDs are gaining popularity for being implemented with an inverted structure for improved air stability. The work function of ITO is reduced to facilitate electron collection or injection in such inverted structures.In many such applications, the work function has a significant impact on the device performance as it affects the energy barrier height at the heterojunction interface. 8 Additionally, applications like thermionic emission and Schottky effect require work function to act as a critical factor to determine the amount of current that can be emitted from a hot cathode. 9,10 Furthermore, determination of work function is of great importance to understand wide range of surface phenomenon in numerous applications utilizing indium tin oxide films. Hence, the work function of ITO is of critical importance. Work function measurements are broadly divided into two categories, absolute and relative measurements. Relative measurements involve probing methods such as Kelvin probe method, which makes use of contact potential difference between the sample and the reference electrode. 11 Absolute measurements employ photoemission, thermionic emission, field emission etc, in order to eject the surface electrons and are extensively characterized to obtain the absolute work function values. The problems with these methods are that they are expensive and i...
Boron carbon nitride (BCN) thin films were deposited by a dual target DC and RF sputtering technique. The films were deposited using various combinations of nitrogen and argon working gases and B 4 C, BN, and C targets. X-ray photoelectron spectroscopy and Fourier-transform infra-red spectroscopy were utilized, respectively, to investigate the changes in chemical composition and bonding that occurred for films deposited under various N 2 /Ar gas flow ratios and DC/RF target powers. The composition and bonding were correlated to separate measurements of the BCN mass density, dielectric constant, Young's modulus, and hardness. All BCN films were observed to have relatively low mass densities ranging from 2.0-2.5 g/cm 3 . BN rich BCN films were observed to be insulating with relatively low dielectric constants of 3.9-4.6 and Young's modulus and hardness values of 110-150 GPa and 5-13 GPa, respectively. BC rich BCN films were observed to be comparatively leaky dielectrics but did exhibit extreme mechanical properties with Young's modulus and hardness values exceeding in some cases 300 GPa and 30 GPa, respectively. Nanoelectronic metal interconnects have many unique nanoscale electrical, thermal, and mechanical challenges.1-3 While dimensional scaling has produced tremendous improvements in transistor performance, 4 it has produced an opposite effect on the associated metal interconnect leading to increased critical path signal delays and possible degradation of the overall integrated circuit performance.5 As the interconnect signal delays are proportional both to the resistance of the interconnect metal and the capacitance of the insulating interlayer dielectric (ILD), new materials with reduced values of resistivity and dielectric permittivity have been sought to mitigate the negative effects of dimensional scaling.5 Since relatively few materials exhibit a lower resistivity compared to the currently utilized interconnect metal copper (Cu), most materials based interconnect delay reduction efforts have focused on implementing new ILD materials with increasingly lower values of dielectric constant (i.e. low-k).6 Unfortunately, the hybrid inorganic-organic silicate (a-SiOC:H) materials currently utilized as low-k ILDs exhibit reduced electrical, thermal and mechanical properties in addition to reduced values of dielectric permittivity.5-7 These overall reduced properties have severely aggravated a variety of interconnect related reliability issues such as time dependent dielectric breakdown and die cracking during packaging. 2,3Compounds in the boron-carbon-nitrogen phase diagram (such as diamond (C), cubic boron nitride (c-BN), and boron carbide (B 4 C)) are potentially attractive as alternative low-k dielectric materials due to their covalent bonding, short bond lengths, and low atomic mass that leads to a unique combination of low dielectric constant but high thermal and mechanical strength. [8][9][10][11][12] Some of the already prominently reported properties for these materials include good wear resistance, hig...
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