Metal ion gun

A versatile Laser-SNMS instrument consists of a versatile microfocus ion gun, a sputtering ion gun, a liquid metal ion gun, a pulsed flood electron gun, a resonant laser system consisting of a pulsed Nd YAG laser pumping two dye lasers, a non-resonant laser system consisting of a high-power excimer or Nd YAG laser, a computer-controlled high-resolution sample manipulator on which samples can be cooled or heated, a video and electron imaging system, a vacuum lock for sample introduction, and a TOF mass spectrometer. 

Figure 15.2 shows the schematic representation of a typical ToF-SIMS device. All the system is placed under high vacuum (typically 10 7 torr) to avoid interactions between ions and air molecules. Primary ions are produced by a liquid metal ion gun and then focused on the sample to a spot with a typical size of less than 1 pm. After they impinge the surface, secondary ions are extracted and analysed by the ToF analyser. To synchronize the ToF analyser, the primary ion beam must be in pulsed mode. 

For SIMS analysis, the sample can be a solid material, a thin layer or particles supported on a substrate. It must be able to withstand ultra-vacuum, since volatile components may be redeposited during analysis. Because of the erosion of the sample during ion impact, any contamination layer can be eliminated prior to analysis. The preparation of the sample is thus subject to less severe conditions than for other surface analysis techniques. For the results of composition profiles to be significant the surface must, however, be flat at the scale of the ion probe. The use of a liquid metal ion gun will enable concentration profiles to be determined on grains of around 0.1 pm in diameter. 

These spectra were obtained from a Poschenrieder TOF instrument equipped with a 30 keV Ga liquid-metal ion gun. The area analyzed was 300 x 300 pm using a total ion dose of 10 ions per cm. ... 

Currently used primary ions are Ar, produced by electron ionization (El) of Ar, or Ga, generated by a liquid metal ion gun (LMIG). Typical beam spot diameters on the sample are 10-25 pm and 50-100 nm... 

A micro-focussed liquid metal ion gun used for raster generated imaging. 

Physical Electronics (Eden Prairie, MN, USA) TRIFTII time-of-flight SIMS (ToF-SIMS) equipped with an liquid metal ion gun. 

IMS experiments can be performed using ME-SIMS or MetA-SIMS. In the cases described here, these experiments are conducted on a ToF-SIMS equipped with an In liquid metal ion gun. The experimental procedure for ME-SIMS and MetA-SIMS data acquisition is identical. 

The ToF-SIMS instrument is equipped with a gallium ( Ga" ) liquid metal ion gun (LMIG) operated at 25 kV (see Note 10). 

These instructions assume the use of a PHI TRIFT III ToF-SIMS instrument (Physical Electronics USA, Chanhassen, MN, USA) equipped with a gold liquid metal ion gun (Au LMIG). They are easily adaptable to other ToF-SIMS instruments with different ion sources. 

Fig. 4.27 A 10 )rm image of In from a sample of InAs quantum dots on a GaAs substrate with an accompanying line scan across the indicated 3.5 pm region of the image illustrates the high lateral resolution capabilities with a liquid metal ion gun in TOF SIMS (data taken with Ga primary ion beam in a PHI TRIPT III)...

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