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Achieving the highest possible resolution using scanning-electron-beam lithography (SEBL) has become an increasingly urgent problem in recent years, as advances in various nanotechnology applications [F. S. Bates and G. H. Fredrickson, Annu. Rev. Phys. Chem. 41, 525 (1990); Black et al., IBM J. Res. Dev. 51, 605 (2007); Yang et al., J. Chem. Phys. 116, 5892 (2002)] have driven demand for feature sizes well into the sub-10nm domain, close to the resolution limit of the current generation of SEBL processes. In this work, the authors have used a combination of calculation, modeling, and experiment to investigate the relative effects of resist contrast, beam scattering, secondary electron generation, system spot size, and metrology limitations on SEBL process resolution. In the process of investigating all of these effects, they have also successfully yielded dense structures with a pitch of 12nm at voltages as low as 10keV.

Recently, vertically aligned carbon nanofiber based dual-gate field emission structures have been fabricated for use in parallel electron-beam lithography, and their electron-beam focus adjustment capability has been demonstrated. This article summarizes the results of a numerical investigation of device behavior due to geometry variation in an effort to better understand device characteristics and performance. The effect of electrode thickness on minimum beam diameter and depth of field (DOF) were investigated for axially symmetric structures using a two-dimensional simulation package. The results indicate both a decrease in minimum spot size from ∼30to∼20nm, and an increase in DOF from ∼1to∼6μm when the focus electrode thickness is increased from 100to500nm. The impact of misalignments of the focus electrode and the carbon nanofiber on the beam behavior was investigated with a three-dimensional simulation package. Results show that reasonably well-converged beams can be achieved even with considerable o...

We briefly describe the basics of electron holography, the hologram formation, as well as its acquisition and reconstruction. Our test sample requires a holographic field of view in the medium magnification range of about 20–30 k×. Two of the microscopes (Philips) utilized for this Round Robin experiment feature a Lorentz lens for medium magnification whereas the third one (Hitachi) requires a special lens current setting in its free lens control mode. The phase images from electron holograms reveal potential differences caused by active dopants. The comparison between the phase images reconstructed from our test holograms taken with the different microscopes show excellent agreement.

The Digital Electrostatically focused e-beam Array direct-write Lithography (DEAL) concept is currently under development at Oak Ridge National Laboratory (ORNL). This concept incorporates a digitally addressable field-emission array (DAFEA) built into a logic and control integrated circuit to function as the write head for an e-beam lithography tool. The electrostatic focusing is integrated on the DAFEA and consists of additional grids lithographically aligned above the emitters and extraction grid, each separated by a dielectric (nominally low-temperature SiO2) layer. Prototypes of the DAFEA have been fabricated and used to test the focusing of the electron beams and to pattern lines in PMMA resist. First lithography tests have used electron energies of 500 eV to pattern lines less than 1 μm wide at a working distance of 500 μm which extrapolates to

Electron holography using a transmission electron microscope equipped with a Moellenstedt biprism has emerged as a viable technique for creating two-dimensional voltage maps of semiconductor devices. We are presenting an introduction to this dopant profiling method. Practical details are given on sample preparation, instrumentational considerations, and data interpretation.

In this article we describe a method for direct epitaxial growth of thin-film structures using a combination of resistless electron beam lithography and supersonic molecular beam epitaxy. Electron beam irradiation of a surface hydride layer on silicon induces hydrogen desorption and hence alters the surface reactivity of the exposed area. Introduction of a source gas concurrently with, or immediately following electron beam exposure results in a pattern formation on the exposed area. Continuous silicon oxide patterns with linewidths below 0.1 μm have been achieved. The resulting pattern can be also used as a mask for subsequent selective growth on the unexposed area. Supersonic molecular beam epitaxy is a highly nonequilibrium film growth method that uses translationally hot source gas species generated by a high pressure gas expansion. Since the reactivity of the source gas molecules depends exponentially on the incident kinetic energy, the chemical selectivity of the film growth process can be altered by tuning the incident kinetic energy. Arbitrary patterns with linewidths on the order of 0.1 μm have been achieved with Si, Ge, and SiC epitaxy on Si (100) and Si epitaxy on Ge (100).

Critical dimension metrology relies on the analysis of electron‐beam signal profiles from structures of arbitrary size and shape. Conventional modeling techniques for simulating such profiles use Monte Carlo techniques which, while very accurate, require considerable computing time since any change in any parameter necessitates a complete new calculation. This paper describes an alternative approach in which a Monte Carlo simulation is used to derive the coefficients of a diffusion matrix. From this matrix the backscattering and secondary electron profiles from a surface of given geometry can be found by simple summation, and the results of a change in the geometry can be determined immediately without the need for further computation. The predictions of this method are in excellent agreement with those of the conventional approach.