TRICON: PROJECT AND VACUUM SOURCE
Some INFM laboratories of surfaces electronic spectroscopies specific requirements (in particular units of the INFM in Modena and Genoa) about the controlled metals thin film increase in UHV (Ultra High Vacuum) have carried the F section of the INFM to finance a plan for the development and construction of evaporation source for electronic strafing. The research, carried out mostly in Modena but in full collaboration with Genoa 's units and the Centro Progettazione Strtumenti INFM of the Sincrotone in Trieste , focused the interest of the productive world: in particular, 2m strumenti of Rome has stipulated one convention with the INFM for the development and realization of the power source of the evaporation source.
The developed instrument introduces various innovating aspects, mechanical, constructive and the base concept of the source itself. An evaporator, called " TRICON ", has been planned, realized and partially tested; Moreover an ingegnerizzation job is in action (has been obtained, in such sense, a financing from the Applicative Network) so as to obtain best performance from the project.
The TriCom source, shortly , allow the evaporation from a long series of elements, at high and low melting point, as conductors or insulators, with the capabilities of fine calibrating the speed of evaporation, constant mantaining it constant through time. All obtained with fine choice of the materials of the source and with the adoption of innovative and originals tecniques. The evaporator is oriented to the sufaces phisics research: thin film depositions from the submonolayer until to high spessors,UHV cleaning, high control of evaporation conditions, long endurance of operation in UHV, minimums maintenance during the use, are its main characteristics.
The electronic of control , realized by 2m Strumenti, comprises: 10V 1A local power source (for warm filament), local power source (250V-100A(grill control , degassing source), local power source HV max 3000v, max 75mA (anode), feedback control. These elements are all inside in an only local power source: this allows the correct rationalization of the negativ and masses, and a minimal use of external cable connection. The CE certification is also obtained for the same apparatus.
HIPERCVD SYSTEMS: CVD Process High Performances Reaction chambers
2M Strumenti Sr l builds and distributes, on exclusive right for Italy , the thin film deposition systems from vapour phase of the HiPerCVD series. These systems are based on a prototype developed by MOCVD Lab. - Innovation Engineering Department of Lecce University ( Patented N. 01304833 ). Fig. 1 picture shows the prototype developed by Lecce University . HiPerCVD systems are related to high performances CVD reaction chambers for endothermic growth processes of both composed semiconductors and oxides and/or metals. Such systems were designed for " custom " type applications , having feaures to be adapted to the particular requirements of CVD process where they have to be used.
General issues:
HiPerCVD systems allows the application of CVD processes both in atmospheric and low pressure. .To get this result, the reaction chambers geometry is manufactured according to fluidodinamic based parameters in order to obtain laminar conditions, absence of memory effects and a complete thermal development of the inside temperature profiles, both using H2 as N2 as carrier gas. The particular substrate location allows its spin by using a gas spinning system, GSS (patented). That allows to get and keep a deposit high lateral uniformity, also over large areas.
Technical Characteristic :
Systems HiPerCVD,semiconductors quartz made, have practically two chambers: a containing outer one and an inner one (liner), which is the real reaction chamber. The susceptor helding the substrates, made on densified pyrolitic graphite, is later coated by a vitreous carbon material (FABMATE®) which is particularly suitable to work on redoxing environmental. Chamber particular geometry and GSS system were designed to be easily scaled according to the customers enquiries to CVD process wafers of 1.5” , 2” and 3” Fig. 3 shows substrate rotation frequency versus H2 flow required from GSS system for atmospheric pressure processes ( figures are concerning 1.5” wafers ) If necessary, chamber can be equipped with an optical windows array, to be used on CVD photo-assisted processes, and/or with in-situ diagnosis and monitoring optical systems.
HiPerCVD systems are complete with flanges and connections, including a loading / unloading door for substrates, and an IR heating lamps system, strip heaters type, 6.5 KW power. If necessary for the customer, such systems can be equipped with flanges to be connected to already existing CVD apparatus. Fluidodynamic HiPerCVD The fluidodynamic behaviour of the gases inside the inner reaction chamber (liner) is simulated during the project utilizing the modern fluidodynamic computing codes. The optimized geometry of the HiPerCVD reaction chambers can guarantee the results shown on fig. 4. When the process temperature is 500°C and H2 flow is 2.0 nl/min, HiPerCVD chambers geometry allows a temperature gradient localized just very close to the substrate, keeping in the meantime the top of the liner at lower temperatures (cold-wall reactor). The path of the fluid stripes on the liner can show the complete gas laminarity very close to the substrate.