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MgO Deposition: ( CpEt ) 2 Mg + H 2 O. April 2014 A. O’Mahony, A. Mane, J. Elam. Early Attempt at Uniform MgO. 70 cycles ( EtCp ) 2 Mg/H 2 O: 6-35-1.5-30 @200 o C MgO measured on Si and MCP MCP located at centre of 9 x MCP holder. Front of MCP Back of MCP. Growth per cycle ( Å/cycle ).
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MgODeposition: (CpEt)2Mg + H2O April 2014 A. O’Mahony, A. Mane, J. Elam
Early Attempt at Uniform MgO • 70 cycles (EtCp)2Mg/H2O: 6-35-1.5-30 @200oC • MgO measured on Si and MCP • MCP located at centre of 9 x MCP holder Front of MCP Back of MCP Growth per cycle (Å/cycle) Location on MCP (cm) • Expected GPC 1.4 Å/cycle: Up to 2x higher GPC on back of MCP compared to front • Non-uniformity in thickness will affect MCP gain Precursor flow
Optimized Process Substrate Layout: top 10 μm dummy MCPs outlet inlet 20 μm monitor MCPs 10 μm dummy MCPs bottom • Wedged holder with 9 x 9” holder for 53 mm MCPs • 30 cycles (EtCp)2Mg/H2O: • 2-120-1-60 @200oC
Measurement of MgO Thickness MgO thickness measured: • On Si positioned beneath 9 MCP holder (8 x 8” Si) • On front and back surfaces of MCP – 5 points in each direction (2 x 2” MCP) Thickness measurement on MCP top top to bottom Inlet Centre Outlet inlet to outlet
Run 040214-1 MgO: (CpEt)2Mg + H2O • Si along length of reactor, 9 x MCPs: 1 monitor (centre) • Si std variation = 4%, GPC = 1.3 Å/cycle (direction: inlet-outlet) • Si std variation = 13%, GPC = 1.5 Å/cycle (direction: top-bottom) • Higher GPC on MCPs than on Si but good uniformity on both MCP surfaces Thickness on Si (8 x 8” Si) Thickness on Centre MCP (2 x 2” MCP) MCP front MCP back Precursor flow Precursor flow Precursor flow
Run 040214-2 MgO: (CpEt)2Mg + H2O • Si along length of reactor, 9 x MCPs: inlet and outlet monitors • Si std variation = 9.0%, GPC = 1.3 Å/cycle (direction: inlet-outlet) • Si std variation = 9.8%, GPC = 1.5 Å/cycle (direction: top-bottom) Thickness on Inlet MCP (2 x 2” MCP) MCP front MCP back Thickness on Si (8 x 8” Si) Thickness on Outlet MCP (2 x 2” MCP) MCP front MCP back Precursor flow
All data: Runs 1 + 2 • Reproducible MgO thickness on Si with 9 x MCPs • Slight depletion in precursor at outer most point of holder (run 2) • Decrease in MgO thickness from inlet to outlet but good uniformity across MCP top and bottom surfaces for all 3 monitor MCPs
Conclusions • Uniform deposition on individual MCPs (front and back surfaces) located at inlet, centre and outlet positions • Decrease in MgO thickness across reactor but precursor depletion only evident at outermost point on outlet MCP Challenges: • Scaling to larger batches of 2 x 2” MCPs or 8 x 8” MCP • Substrates – require NiCr coated substrates for process optimization (need reflective surface for ellipsometry to measure thickness)