Design of an Einzel Lens with Square Cross-Section

In this paper, the results of modeling and simulation of a microcolumn are presented. The microcolumn is part of a developed miniature MEMS electron microscope equipped with a miniature MEMS high-vacuum micropump. Such an arrangement makes this device the first stand-alone miniature electron-optical device to operate without an external high-vacuum chamber. Before such a device can be fabricated, research on particular elements must be carried out to determine the working principles of the device. The results of the calculations described in this article help us to understand the work of a microcolumn with square holes in the electrodes. The formation of an electron beam spot at the anode is discussed. Further calculations and results show the dependence of the Einzel lens size on the electron beam spot diameter, electron beam current, and microcolumn focusing voltage. The results are used to define the optimal design of the developed MEMS electron microscope.

INFLUENCE OF OXYGEN IMPURITIES ON ION BEAM INDUCED INTERDIFFUSION IN THIN Au-Al MULTILAYERS DEPOSITED ON DIFFERENT SUBSTRATES

Au-Al interdiffusion processes in thin layers deposited on various substrates were investigated with RBS during high current ion irradiation. The atomic movements were identified simultaneously (in-situ RBS) with a depth resolution of a few nanometers. It was observed that heating of the specimens due to ion irradiation was the most evident mechanism inducing atom transport. After only 8 min of irradiation with 300 nA 2.0 MeV 4 He + ions (beam spot diameter 0.5 mm), two Au-Al layers (total thickness 600 nm) deposited on glassy carbon or gold were found to be fully interdiffused. In contrast to that, no significant interdiffusion was measured for the same systems deposited on wafer silicon and polished aluminium substrates. To understand this behaviour, depth distributions of oxygen impurities were measured using enhanced elastic backscattering spectroscopy (σ ≈ 102 σ R with 7.6 MeV 4 He ions.

CW Annealing Techniques for Junction Formation in Ge

ABSTRACTCW scanned Argon laser annealing is used to form photo diodes in single crystal Boron implanted germanium. The starting material is doped n–type to 4 × 1015 cm−3 and oriented 2° off the <100>. For annealing, a substrate temperature of 250°C is employed in conjunction with a beam spot diameter of 50 μm and scan speeds in the vicinity of 1 cm/sec. Pyrolytic oxides are deposited to provide a protective and antireflective coating. Devices are fabricated and display dark leakage characteristics of the order of ∼ 10−4 A/cm2 which is comparable to diodes made by more conventional techniques.