A high brightness plasma ion source has been developed to address focused ion beam ͑FIB͒ applications not satisfied by the liquid metal ion source ͑LMIS͒ based FIB. The plasma FIB described here is capable of satisfying applications requiring high mill rates ͑Ͼ100 m 3 / s͒ with non-gallium ions and has demonstrated imaging capabilities with sub-100-nm resolution. The virtual source size, angular intensity, mass spectra, and energy spread of the source have been determined with argon and xenon. This magnetically enhanced, inductively coupled plasma source has exhibited a reduced brightness ͑␤ r ͒ of 5.4ϫ 10 3 A m −2 sr −1 V −1 , with a full width half maximum axial energy spread ͑⌬E͒ of 10 eV when operated with argon. With xenon, ␤ r = 9.1 ϫ 10 3 A m −2 sr −1 V −1 and ⌬E = 7 eV. With these source parameters, an optical column with sufficient demagnification is capable of forming a sub-25-nm spot size at 30 keV and 1 pA. The angular intensity of this source is nominally three orders of magnitude greater than a LMIS making the source more amenable to creating high current focused beams, in the regime where spherical aberration dominates the LMIS-FIB. The source has been operated on a two lens ion column and has demonstrated a current density that exceeds that of the LMIS-FIB for current greater than 50 nA. Source lifetime and current stability are excellent with inert and reactive gases. Additionally, it should be possible to improve both the brightness and energy spread of this source, such that the ͑␤ r / ⌬E 2 ͒ figure-of-merit could be within an order of magnitude of a LMIS.

A liquid metal ion source (LMIS) of Ga + ions has been the mainstay of focused ion beam technology over the past 20 years or so [1]. While state-of-the-art Ga + ion FIB columns typically possess a resolution of < 5 nm, FIB-based transmission electron microscopy (TEM) specimen preparation techniques were initially developed using Ga + ion beams with much broader beams (i.e., ~ 50-100 nm resolution) [2,3].Inductively coupled plasma (ICP) sources [4] have recently been introduced into FIB columns. The ICP source yields worse ultimate resolution than the LMIS FIB within the low current regime, but greatly improved resolution in the high current regime [4]. Thus, the plasma FIB (PFIB) allows for faster removal rates of large volumes using a combination of higher beam currents plus larger mass Xe + ions which increase the sputter yield [5]. The PFIB beam size in the low current regime is similar to the beam sizes first introduced in a LMIS FIB. Therefore, it seems plausible that the PFIB could be used for TEM specimen preparation. Indeed, we present PFIB-prepared TEM results below. Since Xe is inert, Xe + ion bombardment may be preferrable for specimen preparation, particularly for cases where it is well known that deliterious Ga-rich intermetallic phases can precipitate on milled surfaces [7.8]. The high mass Xe + ions also allows for greater throughput via higher sputter yields, and yields less surface damage due to the smaller ion range of Xe + compared to Ga + in a given target. Using SRIM, the sputter yield and longitudinal range for 30 keV Xe + in Si at 0 o incidence is 2.9 atoms/ion and 24 nm respecitively, while that for Ga + at the same conditions is 2.2 atoms/ion and 28 nm respecitvely. SRIM plots showing the ion range and recoil motion of 30 keV Xe + and 30 keV Ga + in Si at 0 degrees incidence are found in FIG. 2. The reduced ion range of Xe + is consistent with the observation of less amorphous damage for Xe + over Ga + (despite the slight differences in ion energy herein). In summary, the PFIB can be used to prepare electron transparent specimens and Xe + ions have tremendous potential as an alternative to Ga + ions for TEM specimen preparation and other applications [9].

The ex situ lift out (EXLO) adhesion forces are reviewed and new applications of EXLO for focused ion beam (FIB)-prepared specimens are described. EXLO is used to manipulate electron transparent specimens on microelectromechanical systems carrier devices designed for in situ electron microscope analysis. A new patented grid design without a support film is described for EXLO. This new slotted grid design provides a surface for holding the specimen in place and also allows for post lift out processing. Specimens may be easily manipulated into a backside orientation to reduce FIB curtaining artifacts with this slotted grid. Large EXLO specimens can be manipulated from Xe+ plasma FIB prepared specimens. Finally, applications of EXLO and manipulation of FIB specimens using a vacuum probe lift out method are shown. The vacuum probe provides more control for placing specimens on the new slotted grids and also allows for easy manipulation into a backside configuration.

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