Robert Stephenson's research while affiliated with imec and other places

... Whilst the application of a dc bias can overcome the observed non-monotonic signal variation, the sample-, environment-and tip-dependence of the appropriate dc bias makes it difficult to apply this approach to unknown samples, in which it may not be clear whether contrast reversal is occurring. Additionally, a continuously applied dc bias may lead to image quality degradation due to damage to the native oxide migration of contaminant species towards the imaging area, or voltage-enhanced tip wear [103]. Hence, these problems with contrast reversal once again illustrate the importance of the development of reproducible sample preparation methods which reliably minimize the density of trapped charge in the oxide layer. ...

... This method, dubbed nano-potentiometry is equivalent to what is referred to as scanning voltage microscopy (SVM) by other groups and in this work. Results of this method applied to a MOSFET can be found in the literature [12,13]. SDVSRM uses the SVM methodology within its first pass of the measurement to obtain the local surface voltage of the sample. ...

... Mahtuvus-aatomjõumikroskoopia (ingk. k. scanning capacitance microscopy, SCM) kasutamise võimalikkust, selle eeliseid ja piiranguid on teiste seas uurinud ka R. Stephenson et al. [6]. Nad analüüsisid kahte ettevalmistatud transistori struktuuri (vt joonis 4). ...

... The fabrication of sharp tips, made using silicon or made using silicon molds, is investigated extensively for a broad range of applications, such as field emission, atomic force microscopy (AFM), and cell research. (1)(2)(3)(4)(5)(6)(7)(8) For typical applications, a robust tip with a high aspect ratio and a small radius is essential. Molded tips, for example made from silicon nitride, diamond-like carbon (9) or metals, (4) are widely used for a range of applications. ...

... ∂C/∂V-mode SNDM measurement, which is a conventional operation mode, exhibits contrast reversal, 13 where same-level response signals are observed for both low and high doping. Contrast reversal often causes problems in the interpretation of observed images. ...

... In semiconductor material, the data can be used to get information about the local distribution of active dopants. Since its introduction in 1992 [9] and the first applications of the method in 1998 [10,11,12], SSRM became an important analysis method for 2D imaging of semiconductor dopant areas with high spatial resolution and high dynamic range. The measurement setup is depicted in Figure 3. ...

... The SCM measurement results for the calibration sample ( Figure S4) and the non-doped nanowire sample ( Figure S5) discussed in this article are given in the Supporting Information. The other mode called scanning spreading resistance microscopy (SSRM) could be a better-adapted alternative tool for the electrical characterization of nanostructures with resolution down to 10 nm in the air 26 and 1 nm in vacuum. 27 Indeed, the repeatability of SSRM measurements in ZnO under ambient conditions is higher than the SCM measurements due to uncontrollable thickness of the water layer which acts as a dielectric. ...

... For microelectronic characterization at the wafer level, both Scanning Capacitance Microscopy (SCM) [6][7][8] and Scanning Spreading Resistance Microscopy (SSRM) [9,10] modes have been implemented to map carrier concentrations of semiconductors with high spatial resolution [5,9,11]. These two electrical modes are contact modes, where conductive tips interact with the sample to probe the local electrical properties [12,13]. Figure 1 presents the Scanning Electron Microscopy (SEM) views of the used probes. ...

... In semiconductor material, the data can be used to get information about the local distribution of active dopants. Since its introduction in 1992 [9] and the first applications of the method in 1998 [10,11,12], SSRM became an important analysis method for 2D imaging of semiconductor dopant areas with high spatial resolution and high dynamic range. The measurement setup is depicted in Figure 3. ...