薄膜中磁控溅射沉积检测方案(在线质谱)

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PLASMA DIAGNOSTICSEOP APPLICATION NOTES Studies of Magnetron SputterDeposition of Thin Films Thin films such as those ofzinc oxide， iridium-tin-oxide (ITO) and titanium nitride are successfullydeposited on a range of substrates by using magnetron sources..Typical arrangements are thosedescribed recently by Matsuda et al (Japan J. Appl. Phys， 36， 4922， 1997) for ITO and by Lee et al (J.Mater. Res. 13， 1260， 1998) for ZnO. Both d.c. and r.f. magnetron sources have been used. It is clear that the quality and growth rate of thedeposited films are strongly influenced by thenature and energies of the species generated atthe magnetron and subsequently arriving at thesubstrate. For example Lee et al say“Eventhough the energy and species in the plasmanear the substrate could not be analysed， it wasbelieved that the effect of highly energeticspecies bombardment on the growing filmsurfacewasdominant at this depositioncondition. It has been reported that the highlyenergetic species， including reflected argon ionsfrom the target， negative ions emitted from thetarget surface， and ions accelerated from theplasma had an average energy as high as severalhundred eV or more (see Tominga et al Jp. J.Appl. Phys. 32， 4131，1993)”. They also quotework in which the bombardment of the growingfilms by energetic oxygen species considerablymodifies the physical， electrical and opticalproperties of the films and their morphology.There is alsogrowingawareness of theimprovements which may be made to such filmsby bombardment using low energy (50eV)ions. The experimental conditions employed in thedeposition systems used by Matsuda et al. andby Lee et al.-gas pressures of 5-20 mtorr，argon/oxygen gas mixtures， discharge powers≈300W， discharge currents ≈ 50 mA - are similarto those which have used elsewhere for thegrowth of titanium nitride films (except for thereplacement of the oxygen by nitrogen). Theexperiments which can be carried out using theEQP include： 1. Residual gas analysis of the processingchamber. 2. Analysis of the processing gas mixturewith the magnetron source switched offor on. This is helpful since operating themagnetron/plasma can frequently generateimpurity traceswhich may affect thegrowing films. 3.. Identification of the ionised species arriving at the sampling orifice of theEQP. Ideally the EQP should be mountedso that it samples through， or close to， thesubstrate. If this is not possible it may bemounted elsewhere in the chamber. TheEQP can be supplied with a samplingorifice plate which can be biased to apositive or negative potential (or with anr.f. signal) to simulate the conditions usedfor the substrate. The instrument samplesboth positive and negative ions. 4.. Measurement of the energydistributions of the various ion speciesarriving at the grounded or biasedsampling electrode. The standard EQPenergy range is ±100eV， higher ranges areavailable. Again positive or negative ionsmay be examined. 5. Identification off ttlhe neutraall sspeciesarriving the samplinggeelectrodeValuable informationcan often beobtained by carryingout thresholdionisation studies of the neutral speciessampled from the plasma or， in the use ofelectronegative species by examining theirelectronattachmentbehaviourraaltlowelectron energies. Experimental Data As examples of data acquired， figures 1， 2 and 3show measurements obtained in a TiNdeposition system. Figure 1： An RGA scan taken with anArgon/Nitrogen gas mixture admitted to the reactorand the magnetron operating using a titanium target. Figure 2： A partial spectrum of thie FOPe positive ionsarriving at the EQP， showing TiNt and other ions，including traces of the unusual compounds TiAr andN2Ar generated in the plasma. HIDEN ANALYTICAL LTD420 EUROPA BOULEVARDWARRINGTON WA5 5UN ENGLAND Tel：+44 (0) 1925 445225 Fax： +44 (0) 1925 416518 E-mail： sales@hiden.demon.co.uk. Figure 3 ： An energy distribution for the argon ionsreflected from the magnetron to the EQP when thebias conditions gave low energy (≤5 eV) ions. Application Note aHiden Analytical