CIG B5. Capitolato Tecnico Technical requirements

Transcription

1 Gara a procedura aperta per l'affidamento della fornitura di uno strumento per X-ray Photoelectron Spetroscopy (XPS) destinato alla Nanochemistry Facility dell Istituto Italiano di Tecnologia CIG B5 Capitolato Tecnico Technical requirements

2 The Nanochemistry facility at IIT needs an Instrument to perform X-ray photoelectron spectroscopy that aims at advancing the characterization of nanostructures, fabricated by chemical approaches, as building blocks for engineered self assembly architectures across multiple length scales, from the molecular level up to the macroscopic world. The steps of synthesis and functionalization of nanomaterials require chemical characterization of material surfaces that could not be easily obtained from other bulk techniques. The use of the XPS, whose sampling depth is less than 10nm (i.e. surface analysis) could drastically contribute to develop new strategies of synthesis and to gain important insight both into nanomaterials and bulk materials. XPS characterizations could be used to support the research activities of all IIT departments that work on materials for different kind of applications. For these reasons the instrument proposed must be scalable with time, due to the continuous evolution of the research topics of IIT. A high versatility in terms of the possibility to integrate the system with additional components and optional is a fundamental requirement. The XPS instrument must be able to obtain qualitative (low spectral resolution) chemical analysis, elemental chemical composition through acquired high resolution spectra of all materials, from conducting to insulating ones, like as an example: metals, semiconductors, polymers and topographically difficult materials like 3D porous polymeric scaffolds or powders. A high spatial resolution (less than 15µm) spectroscopy is highly desired to have the possibility to gain the most important information from the nanomaterial point of view. A good characterization with a small spot (high counts per seconds specification) will be one of the most important criteria that will be evaluated. The instrument of IIT interest must be able to perform, in UHV environment, surface analysis using, as excitation source, both non monochromatized twin anode (Mg Kα and Al Kα ) and Al-Kα monochromatized X-ray beam, and an hemispherical electron analyzer. Moreover the instrument must be a fully multi-technique tool allowing the installation and use, at their top performances, of UPS source and twin anode. The possibility in future to perform Auger Electron Spectroscopy is desirable including REELS The instrument must be able to perform all the analyses on samples that are thicker than 5 mm whatever their nature is, without any problem of charge compensation. A stage having 5 degree of freedom (i.e. x, y, z, angle with respect to the analyzer and compucentric rotation) in chamber of analysis is required. The ability to image and chemically mapping the area of analysis with a high spatial resolution is one of the most important features due to the latest research developments at IIT concerning synthesis of nanoparticles. The system must be able to perform angle resolved XPS (ARXPS) analyses in automated way by collecting all the information in a fast way and with high energy and spatial resolution. It is tightly requested that the instrument maintains the exact position of the sample at all angles by applying an autofocus and contemporary automatic charge 2/9

3 compensation during the ARXPS analysis. The instrument must be able to perform depth profile with Ar ion source and it must be arranged to be integrated with a polyatomic source if future research lines at IIT requires the use of this option (eg. sputtering of soft homogeneous materials for cleaning and depth profile). During the sputtering with Ar ion source and in the future with polyatomic ion source the equipment must have the ability to maintain a constant charge neutralization and constant binding energy peak position whatever the nature of the resulting interface is. In the future if both polyatomic and Ar ion guns are present on the instrument, the ability of equipment to perform sputtering with the two guns alternatively or simultaneously is required without compromising the possibility to work at a low Ar ion beam voltage (below 200eV). A hot/cold stage (-120 C to 500 C) with a thermocouple monitor on the sample holder is highly desired in the chamber of analysis with the possibility to maintain all 5 degree of freedom over the entire temperature range. A similar option (cool/hot sample holder) is required for the intro-chamber with the same performances in terms of temperature. If required in the future, upgrading the instrument with additional extensions has to be readily carried out, e.g. pre-treatment chamber for heterogeneous catalysis, an UHV chamber for thermal desorption spectroscopy and etc., all of which need to be connected through a radial distribution chamber. 1. DETAILED INSTRUMENT DESCRIPTION The system should meet or exceed the following specifications. All the specifications indicated below must be obtained on the system before shipment. They must also be obtained using X-ray power recommended for routine analysis without scaling of the count rate. Where sensitivity and lateral resolution are specified these must be demonstrated simultaneously with the sample in the same position for each measurement. The system must be assembled and tested before shipment. It must obtain all the values indicated in the following specifications tables if the relevant source is supplied. The calibration of binding energy must be performed by choosing Au, Cu and Ag as reference materials. Silver (Ag3d spectrum) must be used as a material of reference to assess sensitivity of detection. The performances of ion sputtering, in terms of ion beam energy and incidence angle, must be defined by means of the analysis of SiO 2 /Si, or Ta 2 O 5 /Ta. Polyethylene therephtalate and polytetrafluoro ethylene will be considered as standard material to assess the performances of neutralization of insulating polymers and performances of sputtering by means of polyatomic source. The possibility to have reliable results on stoichiometry, a complete library of sensitivity factors, of well know inorganic materials whatever their nature is one of the most important feature that will be evaluated. 1.1 System 3/9

4 The system must be equipped with an intro chamber and a chamber of analysis and some other components connected to it (see below). The chamber of analysis must be of Mumetal to perform, in future, Auger spectroscopy. The Intro chamber, the analysis chamber and all the components should allow UHV conditions in the analysis chamber, the minimum pressure obtainable should be stated below; the chamber should shield the sample from external magnetic fields and allow the installation, later, of additional «optional analysis tools»like as an example the equipment needed for Auger electron spectroscopy (AES) a polyatomic ion gun for polymer depth profiling or a glove box. Particular care must be dedicated to the alignement and dimensions of the ports and to the materials used, so as to reduce evacuation time and pressure recovery. The vacuum in the analysis chamber have to be better than 5E10-10 Torr after baking of the system with no samples inside the chamber of analysis; in the intro chamber the pressure must be less than 10-8 Torr. Fast Entry Air Lock should allow fast sample insertion in the analysis chamber. The pumping system should allow fast pump down time and fast recovery. During ion gun sample cleaning at typical operating pressure the pressure must be not higher than two orders of magnitude with respect the base pressure with samples inside the chamber, while, in case of the presence of an electron flood gun as charge compensation system, the pressure must be not higher than one order of magnitude with respect the base pressure with samples inside the chamber. Vacuum recovery time after ion gun sample cleaning at typical operating pressure and after flood gun use should be indicated. An integral baking system built into the structure of the spectrometer is required. This integral baking must be complete with automatic timer and all the components necessary to minimize cold spots and provide an average baking temperature up to150 C. A fitted flexible baking cover must be included with the equipment. Different programs of baking must be available for the operator to be changed depending on the status of the machine. Concerning the pumping system, the supplier should be able to provide Ion pumps, turbomolecular pumps (rough pumping) with rotary backing pumps on different chambers (i.e. analysis chamber and intro chamber ) and a combination of differential ion pump and Titanium sublimation pump (TSP). A combination of Ion / Pirani gauge for pressure measurement of the analysis chamber is required. Continuous monitoring and logging of vacuum system parameters and an automatic control and interlock of all valves is also required for the introduction of the sample to the analysis chamber. The pumping arrangement for the introduction and analysis chamber must be designed specifically for automated vacuum control and integrated with the software and hardware functions of the system. 4/9

5 1.2 Sample handling Sample holder The sample holder minimum 50 mm in diameter must be able to fit a number of samples no less than 10 of 5mm in diameter). Three sample holders with these characteristics must be purchased to speed up the time of analysis. A sample holder for heating/cooling and one for compucentric rotation must be included in case the same sample holder cannot be used for the three operations. All the accessories to opportunely fix the samples on the sample holder must be included. In case of thick samples, when the instrument is not able to perform the analyses with standard sample holder, a specially designed one for this particular use must be included in the instrument equipment list. Sample holders with a mounted sample must be transferred into and out of the analysis chamber using a rack-and-pinion or magnetically coupled transfer rod. A Hot/Cool (H/C) system is required for the intro chamber. In the chamber of analysis and intro chamber with a nominal temperature range of -120 C to +500 C In case of standard sample holders which are used with the ambient stage cannot be used with the H/C stage, sample holders designed for the H/C stage must be supplied with this option Stage The maximum sample thickness to be inserted in the system must be no less than 10mm. The sample stage in the analysis chamber must be controlled by the computer system managing all other functions of the XPS system. A remote internet control is desirable for the instrument. A laboratory license for data processing software is a valuable option for the instrument. The system must have the ability to define and store different analysis positions and have the ability to return to these positions with high precision for automated analysis. The stage must have X, Y, Z, Rotation and Tilt capability to enable precise positioning of the sample. Moving along Z must enable the analysis of samples up to 10 mm thick. The movement along the axis Tilt must tilt the sample between 0-90 degrees with respect to the analyzer in order to automatically carry out analytical ARXPS mode in case the instrument cannot collect the information of ARXPS without tilting the samples. The stage must have the ability to heat and cool the samples between -120 C and +500 C while maintaining the ability to control all 5 axes of the sample stage. Bakeable motors on all axes are required Specimen viewing X-ray shielded viewports on all the chamber of the system. Microscope specimen alignment facility with high-resolution, color CCD TV video camera and digital zoom facility 5/9

6 Microscope is required for easy sample navigation. LED light source for illumination is preferable. Other forms of imaging such as x-ray induced secondary electron imaging are desirable Analyzer and detector Electron Energy Analyzer should have 180 deflection and a mean radius of at least 150mm or higher. It should be fitted with a multi-channel detector, for high sensitivity XPS spectroscopy, and 2-dimensional XPS imaging. The multi-channel detector must have a large dynamic range of > 1 Mcps. It must be possible for the user to limit the area of analysis to 15 µm or better for small area applications. The system must be optimized for angle resolved XPS studies and solid angle of collection must be +/- 4 degrees. The energy resolution the full width at half maximum (FWHM) will be better than 0,5eV determined on Ag3d 3/2 peak. At 0,6eV resolution the count rate must be higher than 100,000CPS. The instrument should have at least the following performance for large area and small area monochromated XPS: the count rates warranted on Ag3d 3/2 peak working at high energy resolution must be at least higher than 10 6 cts*s -1 for large area (energy resolution better than 1.0eV) and better than 3000 cts*s -1 for 20µm area of analysis (energy resolution better than 0,6eV). The highest performance at the smallest area for spectroscopy for nanotechnology applications is the highest desired capability for the new instrument. The performance specifications at additional smaller areas is requested Multipoint spectroscopy must be performed with a spatial resolution of 10µm or better. A snapshot mode must be available with a high number of channels. The snapshot spectra must be effectively used to identify chemical shifts and fingerprint different chemical species for post analysis processing of maps and sputter depth profiles based on snapshot spectra. Magnetic and/or multi-element electrostatic input lenses, computer programmed are requested to generate a good XPS imaging. It must be possible to collect XPS chemical maps rapidly. For reasons of speed and avoiding sample damage parallel acquisition of images must be possible. The ultimate resolution within the image of <3 µm is desirable. The supplier should be able to demonstrate that images and spectroscopy data are collected within the same point of the sample up to the ultimate spatial resolution 1.3 Sources and Charge neutralizer system Achromatic and X-ray monochromatized source The X-ray Photoelectron system must be equipped with a monochromatized AlKα source which allows spectral information from areas less than 20µm dia. to 300µm dia. The 6/9

7 minimum x-ray spot size on the sample shall be specified. The cooling system (chiller) for this source must be provided with the XPS system. The maximum anode power should be specified together with anode lifetime. A multi-position x-ray anode is desirable. Twin anode source, if not bought initially must be straight forward upgrade. Mg/Al anode achromatic source mounted on linear retractor with a mechanism for optimal positioning of each source face. The dual anode must operate at a nominal operating voltage of 15kV and a maximum power of 400W Ion gun The X-ray Photoelectron system must be equipped with an argon gun to clean the samples, to perform depth profiles and to be used for charge neutralization for insulating samples, if the system provides for this. This gun must be able to operate at 100V - 4kV. To keep a high current at low energy, the gun must be designed with a floating ion column. The gun must be differentially pumped and the gas introduction must be easily controlled to maintain constant the ion density during long sputtering. The maximum current of sputtering must be at least 5µA at 5KV. All electronic parameters for the ion gun must be under full digital control of the data system. The spot size must be better than 200µm and the possibility to raster this beam is necessary. If the system permit to use the ion gun as an analytical tool this must be stated (ISS, scattered electrons imaging) Polyatomic ion gun The system must be designed to allow a future addition of a polyatomic source that could be installed in the future. This addition must be realized without compromising the correct function of the instrument UPS source A windowless discharge source of fully bakeable metal and ceramic construction, which is readily optimized for maximum He (I) or He (II) (or Ne (l)/ne (ll)) output. The lamp must be differentially pumped. The pumping system should also be supplied and integrated with the one of the main system. Sensitivity higher than 1,000,000 cps at 120 mev resolution is required Charge compensation: The equipment must be fitted with a charge compensation system to minimize the the effect of induced charge during the analysis of insulating materials. Flood gun should allow efficient charge compensation on insulating samples even if patterned, porous and 7/9

8 micro and nano-structured. Electron energy must be very low. The neutralization technology must be specified. The resolution in terms of FWHM of the ester component ( C-C(=O)-O-) at ca.289 ev of the C1s peak of PET, must be less than 0.85 ev with cps higher than 2000 at 100um of analyzed area. The flood gun must be controlled by computer. The charge neutralization system shall be capable of self regulating and must work automatically for most types of samples without any intervention during multi-sample analysis. In case of very complicated samples (i.e. porous scaffolds) an alternative adjustment of the charge compensation (i.e. different programs of work) could be required. 1.4 Software and Data Processing All the devices controlled by data system should be listed. It should allow an easy configuration of all experiment parameters. Data system software should allow control, acquisition, processing and printout for provided techniques (XPS, SAXPS, ISS, UPS, AES). Data system should also perform line-scans, imaging, multi-point analysis, multispecimen analysis and depth profiling. Data processing with all the most frequent tools like qualitative and quantitative analysis, best fitting procedures, normalization, background subtracting etc... is required. A windows cascade showing all the spectra during the acquisition is required. The computer operating system must be indicated together with the computer specifications. The interface between the computer and the instrument must be versatile. Remote internet control of the system is desired. If any third party software is required that should be stated. Up to 5 licenses or a laboratory license is required. 1.5 Installation Installation must be performed by the vendors engineers or approved agent of the company that will provide the instrument. Installation will follow successful completion of the site survey confirming that the requirements of the Site Preparation Guide are met. Installation will include the following: -Assembly of the instrument to the layout detailed in the current specification documents -System start-up and basic functionality testing -Operation and performance testing -Performance and documentation of agreed specifications -Three/four days of hands-on analytical training by a laboratory scientist of the company at the user s site three to six months after system installation. An advanced training must be scheduled within one year of installation. 8/9