Preparation of TEM samples by focused ion beams

Author(s):  
John F. Walker ◽  
J C Reiner ◽  
C Solenthaler

The high spatial resolution available from TEM can be used with great advantage in the field of microelectronics to identify problems associated with the continually shrinking geometries of integrated circuit technology. In many cases the location of the problem can be the most problematic element of sample preparation. Focused ion beams (FIB) have previously been used to prepare TEM specimens, but not including using the ion beam imaging capabilities to locate a buried feature of interest. Here we describe how a defect has been located using the ability of a FIB to both mill a section and to search for a defect whose precise location is unknown. The defect is known from electrical leakage measurements to be a break in the gate oxide of a field effect transistor. The gate is a square of polycrystalline silicon, approximately 1μm×1μm, on a silicon dioxide barrier which is about 17nm thick. The break in the oxide can occur anywhere within that square and is expected to be less than 100nm in diameter.

Author(s):  
H. Wu ◽  
D. Ferranti ◽  
L.A. Stern ◽  
D. Xia ◽  
M.W. Phaneuf

Abstract Gallium focused ion beams (Ga-FIB) have been used historically in the semiconductor industry for failure analysis, as well as circuit edit. However, in spite of the best of these efforts, as integrated circuit dimensions continue to shrink, Ga-FIB induced processes are being driven to their physical limits. The main purpose of this paper is to report the helium and neon ion beams' induced chemistry, including metal deposition, dielectric deposition, and chemically enhanced etching. Two simple examples are shown as proofs of concept demonstrating gas field ion source (GFIS) development for circuit edit applications. The paper summarizes the general utility of helium and neon ion beams for metal deposition, dielectric deposition, and sputtering and etching processes, and discusses some of the technical challenges associated with current GFIS technology. Using GFIS ion beams, it has been observed that the top and buried metal lines can be cut precisely and then reconnected.


1990 ◽  
Vol 182 ◽  
Author(s):  
N. Lifshitz

AbstractPolysilicon gates are an important element of modem MOS integrated circuit technology. The workfunction difference (ϕps) between the polysilicon gate and the silicon substrate is a vital parameter of the MOS system because it determines the threshold voltage of the field-effect transistor. Ideally, ϕps is determined by the doping level in both polysilicon and the substrate. In reality process variations influence the ϕPS in a tangible way. Some of these effects are reviewed in the present paper.


1981 ◽  
Vol 10 ◽  
Author(s):  
Billy L. Crowder

ABSTRACTThe advent of very-large-scale integration in microelectronics has been achieved by reduction in lithographic dimensions coupled with a corresponding decrease in vertical dimensions in properly scaled device structures. This development has placed severe demands upon interconnection technology. The practice of using semiconducting regions (diffusions or polycrystalline silicon) for interconnecting devices is no longer viable because of the high resistance associated with such regions (i.e. interconnections do not “scale” properly). One solution to this problem is the use of multilevel metallization, but this requires tens of thousands of small contacts to shallow diffusions. Refractory metals such as titanium are being explored as materials which provide the necessary stable low resistance contacts suitable for integrated circuit applications. Another solution to the problem is to develop a higher conductivity material to replace or supplement polycrystalline silicon. Refractory metal disilicides have been extensively investigated for this application -both as a direct replacement for polycrystalline silicon or in a silicide/polycrystalline silicon composite (polycide). A critical review of the present status in both these areas will be presented. Emphasis will be upon our experience gained in conjunction with the development of a 1 μm silicon gate metal/oxide/ semiconductor field effect transistor technology.


2018 ◽  
Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
M.L. Ray ◽  
P.E. Fischione

Abstract Transmission electron microscopy (TEM) specimens are typically prepared using the focused ion beam (FIB) due to its site specificity, and fast and accurate thinning capabilities. However, TEM and high-resolution TEM (HRTEM) analysis may be limited due to the resulting FIB-induced artifacts. This work identifies FIB artifacts and presents the use of argon ion milling for the removal of FIB-induced damage for reproducible TEM specimen preparation of current and future fin field effect transistor (FinFET) technologies. Subsequently, high-quality and electron-transparent TEM specimens of less than 20 nm are obtained.


2006 ◽  
Vol 960 ◽  
Author(s):  
Philipp M. Nellen ◽  
Victor Callegari ◽  
Juergen Hofmann ◽  
Elmar Platzgummer ◽  
Christof Klein

ABSTRACTWe present a closed approach towards direct microstructuring and high precision prototyping with focused ion beams (FIB). The approach uses the simulation of the involved physical effects and the modeling of geometry/topography during milling while the ion beam is steered over the surface. Experimental examples are given including the milling of single spots, trenches, rectangles, and Fresnel lenses. Good agreements between simulations and experiments were obtained. The developed procedures can also be applied to other FIB prototyping examples.


1999 ◽  
Vol 595 ◽  
Author(s):  
M. Kuball ◽  
M. Benyoucef ◽  
F.H. Morrissey ◽  
C.T. Foxon

AbstractWe report on the nano-fabrication of GaN/AlGaN device structures using focused ion beam (FIB) etching, illustrated on a GaN/AlGaN heterostructure field effect transistor (HFET). Pillars as small as 20nm to 300nm in diameter were fabricated from the GaN/AlGaN HFET. Micro-photoluminescence and UV micro-Raman maps were recorded from the FIB-etched pattern to assess its material quality. Photoluminescence was detected from 300nm-size GaN/AlGaN HFET pillars, i.e., from the AlGaN as well as the GaN layers in the device structure, despite the induced etch damage. Properties of the GaN and the AlGaN layers in the FIB-etched areas were mapped using UV Micro-Raman spectroscopy. Damage introduced by FIB-etching was assessed. The fabricated nanometer-size GaN/AlGaN structures were found to be of good quality. The results demonstrate the potential of FIB-etching for the nano-fabrication of III-V nitride devices.


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