Howling, Alan

Infoscience - École polytechnique fédérale de Lausanne

1 aah Diagnostics for large area RF plasma reactorsAlan Howling Ecole Polytechnique Fédérale de Lausanne (EPFL), SwitzerlandCenter for Research in Plasma Physics (CRPP)start by acknowledging:Christoph Hollenstein, Laurent Sansonnens, & co.A. Howling, Nankai University March 28 - April 3 (2010)2 aah RF transmission lineprocessgasRF electrode with showerheadprocesspumpsubstrateplasmapumpinggridglass substrate(about 1 m2)loading/unloading portpumping gridsSchematic drawing of a rectangular parallel plate RF capacitive plasma reactor:3 aah passive voltage probe,  1/100groundedreactorRF inter-electrode voltage in vacuumoscilloscope(floating)RF tip andground tip of the probemeasure the RF voltage betweenthe electrodes at each position4 aah RF inter-electrode voltage in vacuumRF power side connection5 aah RF inter-electrode electric field in vacuumusing a diode probe J. Appl. Phys. 95 4559 (2004)probe inserted through holes in a side wall 6 aah E-field relative profile at 100 MHz(bench test with scanning probe) 0 0.2 0.4 m0.20.40.80.60.40.201ElectromagneticmodelingJ0(k0 r)IN VACUUM1 metreJ. Appl. Phys. 95 4559 (2004)RF inter-electrode electric field in vacuumusing a diode probe7 aah reactor 47 x 57 cm281 surface probes for DC voltage and current measurementssurface electrostatic probes:  (i) ion saturated current8 aah surface electrostatic probes:  (i) ion saturated current9 aah 1 metreCylindrical  reactor  experimentJ. Appl. Phys. 95 4559 (2004)optical emission &  surface electrostatic probessurface electrostatic probes:  (i) ion saturated current10 aah 0.750.51Teflon Lensfor 69 MHz0 0.2 0.40.20.4 m10 mTorr 100 mTorr{J0(εeff0.5k0r)}20.510.750.250Probe array: ion current normalized to centerParallel Platesfor 69 MHzsurface electrostatic probes:  (i) ion saturated currentJ. Appl. Phys. 95 4559 (2004)11 aah EXPERIMENTS  AT 100 MHz0 0.2 0.4 m0.20.40.510.750.2500.5 Torr10 mTorrprobe array ion saturation currents(normalized to the central values)200 W{J0(3.5 k0 r)}21 metreJ. Appl. Phys. 95 4559 (2004)surface electrostatic probes:  (i) ion saturated current12 aah Idc, VfDC floating  voltages  give approx. variation in RF  plasma  potentialDC currents  to  grounded  probes  give  DC  current  density  profile,surface electrostatic probes:  (ii) DC floating voltage13 aah perturbation to plasma RF potential due to sidewall areasurface electrostatic probes:  (ii) DC floating voltage14 aah Large area:constant, but      varying   according to the telegraph equation0 V xplasma bulkplasmaground electrodeRF electrodeŨgUgU U~ Equation cannot be satisfied simultaneously over the electrode areaiecirculating current eiŨrfUrfVsb⎥⎥⎦⎤⎢⎢⎣⎡⎟⎟⎠⎞⎜⎜⎝⎛+⎟⎟⎠⎞⎜⎜⎝⎛=→=+∫eeeieTie TUTmMTUdtJJT~Iln3.2ln20)(1 o0Local ambipolarity for 0 time averaged conducting currenton the electrodeBlocking capacitorSmall area:UU ~and constant over the electrode areasurface electrostatic probes:  (iii) DC current, zero bias15 aah surface electrostatic probes:  (iii) DC current, zero bias16 aah 1 metreCylindrical  reactor  experimentoptical emission &  surface electrostatic probesJ. Appl. Phys. 95 4559 (2004)optical emission intensity: fibre optic probes17 aah J. Appl. Phys. 95 4559 (2004)optical emission intensity: fibre optic probesfibre optic telescopefibre optic telescope,for right-angle view18 aah Optical emission 2D profilesin a rectangular reactor:Parallel platesWith lensoptical emission intensity: fibre optic probes19 aah Film thickness measurements, ex situ,telegraph effect Plasma non-uniformity convoluted with gas flow non-uniformity etc.ex situ film thickness measurementstelegraph model 20 aah Film thickness measurements, ex situ,standing wave correction Plasma non-uniformity convoluted with gas flow non-uniformity etc.no lenswith lensex situ film thickness measurements21 aah ex situ film thickness measurement:  interferogram22 aah ex situ film thickness measurement:  interferogramnon-uniformity due to powdernon-uniformity due to standing wave(VHF frequency)37 cm x 47 cm23 aah interference filtervacuum chamberplasma reactorwindowsgrids57 cm47 cmCCD  cameraargon laser beam at 488 nmbeam expanderlight scattering from powderMRS Symp. Proc. Vol. 507Amorphous and MicrocrystallineSilicon Technology,pp547-557 (1998).24 aah OES and electron temperature  vs timeH2* emission is only from e+H2 collisions,but H* emission has several sourcestime

Diagnostics and Simulation for Large Area RF Plasma Deposition Reactors

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Diagnostics and Simulation for Large Area RF Plasma Deposition Reactors

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Infoscience - École polytechnique fédérale de Lausanne