Load-lock system

There are several types of deposition chamber configurations (Fig. 2). The batch-type system is the most commonly used, but the requirement that the system be returned or let-up to ambient pressure on each cycle can pose problems in obtaining a reproducible processing environment. The load-lock system and the in-line system allows the deposition chamber to be kept under vacuum at all times and the substrates introduced and removed through... 

Commercial spectrometers are usually bakeable, can reach ultrahigh-vacuum pressures of better than 10" Torr, and have fast-entry load-lock systems for inserting samples. The reason for the ultrahigh-vacuum design, which increases cost considerably, is that reactive surfaces, e.g., clean metals, contaminate rapidly in poor vacuum (1 atomic layer in 1 s at 10 Torr). If the purpose of the spectrometer is to always look at as-inserted samples, which are already contaminated, or to examine rather unreactive surfaces (e.g., polymers) vacuum conditions can be relaxed considerably. 

By using a multichamber system [129], exchange of residual gases between successive depositions will be strongly decreased, and very sharp interfaces can be made. Furthermore, the use of a load-lock system ensures high quality of the background vacuum, and thus low levels of contaminants in the bulk layers. Multichamber reactor systems have been used for the fabrication of solar cells, and considerable improvements in energy conversion efficiency have been achieved [130, 131]. 

Loading waveform, 13 482-483 Load limits, in waste collection, 25 870 Load-lock system, 24 724 Load variable, 20 666 Lobeline, 2 82... 

Cr-O-Si cermet layers were prepared by RF-sputtering of a Cr 0 Si target (Leybold-Heraeus Co.) with a nominal atomic ratio of 1 1 1, onto thermally oxidized silicon wafers in a Leybold-Heraeus Z 801 load lock system as described in [86]. The thicknesses of the cermet layers were in the range of 100-200 nm. The SiO < layer was deposited in a Balzers-BAK 550 box coater by electron beam evaporation of an SiO. x 1) source material at lO Pa, onto an oxidized Al substrate at 300°C. Typical atomic ratios of Cr 0 Si = (0.8-l) (Ll-1.2) (l) for the cermet and of 0 Si = 1.3 1 for the SiO, layer were measured by RBS for the as-deposited layers, with homogeneous in-depth distributions of the constituents. The samples proved to be completely amorphous in the as-grown state as shown by both XRD and selected arc electron diffraction (SAED). Trace amounts of a CrjSi phase were found only after heat treatment at 600°C. 

Electrocatalytic activity of supported metal particles has been investigated on surfaces prepared in an ultrahigh vacuum (UHV) molecular beam epitaxy system (DCA Instruments) modified to allow high throughput (parallel) synthesis of thin-film materials [Guerin and Hayden, 2006]. The system is shown in Fig. 16.1, and consisted of two physical vapor deposition (PVD) chambers, a sputtering chamber, and a surface characterization chamber (CC), all interconnected by a transfer chamber (TC). The entire system was maintained at UHV, with a base pressure of 10 °mbar. Sample access was achieved through a load lock, and samples could be transferred... 

Hot reactor walls are sometimes used as a means to increase the density of the films that are deposited on the walls. This reduces the amount of adsorbed contaminants on the walls, and leads to lower outgassing rates. A hot wall is particularly of interest for single-chamber systems without a load-lock chamber. Material quality is similar to the quality obtained with a cold reactor wall [145],... 

FIG. 5. Schematic representation of the ASTER deposition system. Indicated are (I) load lock. (2) plasma reactor for intrinsic layers. (3) plasma reactor for />-type layers. (4) plasma reactor for t -type layers, (5) metal-evaporation chamber (see text). (6) central transport chamber. (7) robot arm. (8) reaction chamber, (9) gate valve, (10) gas supply. (11) bypass. (12) measuring devices, and (13) tur-bomolecular pump. 

Figure 6. Plan of the target preparation facilities consisting of UHV preparation chamber (a), (reactive) ion etching chamber (b), ion etching gun (c), laser (d), photon detector (e), transfer arms (f), Auger system for surface analysis (g), sample manipulator and annealing facility (h), load lock and optical microscope for viewing sample (i), evaporator (j), transmission diffractometer (k), and vacuum tank for main spectrometer (1).

UHV surface preparation and analysis chamber, a variable pressure STM chamber, and a load lock and sample transfer system. Fig. 11 shows a schematic of the system. 

The metal-on-polymer interface has been the most studied Interface as metals can conveniently be deposited by evaporation in situ 1n a controllable fashion in a UHV system (26-33). In the case of polyimide, Cu and Cr have been the most studied metals but other metals including N1, Co, Al, Au, Ag, Ge, Ce, Cs, and Si have been studied. The best experimental arrangement includes a UHV system with a load lock Introduction chamber, a preparation chamber with evaporators, heating capabilities, etc., and a separate analysis chamber. All the chambers are separated by gate valves and the samples are transferred between chambers under vacuum. Alternative metal deposition sources such as organometall1c chemical vapor deposition are promising and such techniques possibly can lead to different interface formation than obtained by metal evaporation(34). 

The model molecules which are solid at room temperature (except for benzene), were evaporated from a source consisted of a borosilicate glass container with a small opening, like the design of a Knudsen cell. The source was mounted inside a heatable and coolable copper shaft, that could be inserted to the vaccum system through a load-lock arrangement. Upon heating, the pressure was... 

Fig. 11.5. Sketch of the MAJESTIX setup. The vacuum system is divided into a preparation chamber and a particle-beam chamber, separated by a gate valve. The preparation chamber is also used as load lock. The main components in the particle-beam chamber are the ion gun system, comprising a Wien filter and deceleration...

Similar limiter blocks have been inserted through vacuum lock systems, exposed to higher heat loads and diagnosed in detail in- and ex-situ as well. 

The second chamber is evacuated by a vertically mounted turbomole-cular pump. It hosts a Maxtek BHS-150 quartz microbalance in order to monitor the intensity of the cluster beam, and offers the possibility to connect other UHV systems (such as a load-lock chamber and/or an analysis facility). Cluster deposition on a substrate can be performed directly in the second chamber. 

Fig. 5.6 A schematic drawing of the VG ESCALAB 220i-XL photoelectron spectroscopy system. An analysis chamber, a multi-port carousel chamber, an evaporation chamber and a sample load-lock chamber are shown.

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