Non-Contact Gap Measurement Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement The eq. for the FE current is: In order to predict the gap distance: Set 1st gap going into contact: reference position. Record (I,V,Beta) Increase/decrease the gap with micrometer wihout going into contact. Record sets of data (I,V,Incx). Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Overview of data sets: Data Data 1 Data 2 Data 3 Data 4 Data 5 Data 6 Spot X Spot X Spot X Spot Y Spot X Spot X Spot Y (Bad) (Good) (Bad) (Bad) (Good) (Bad) (Bad) 1 Beta meas. FN Eq. 3 Beta meas. Least-squares System I System II Method? Repeat.? Spot? Microm. Cal.? Repeat.? Contact? Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement 1st method: All lines have approx. same slope, only intercept varies Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement 1st method From reference line get the value of Ae: Considering Ae to be constant, Beta can be calculated from the interception point of each line And the gap d from each of the corresponding intercept Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Problem: Beta can’t be reproduced for the same gap, lines are displaced even for the same gap. (14.4-21.02)um FE1-FE6: 20.16 um FE4-FE7: 18.72 um Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement 2nd method Measure FE several times (x3) for each gap. Apply a non-linear fit to all the obtained lines, i.e. minimized the least-squares. [X’s] = [1/V] [Y’s] = [ln(I/V^2)] [Y’s] = f (Ae, Beta, Inc x) Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 1 (System I) Spot X (contact) Ref: FE1 line FE1-FE9: 14.4um (ref) FE2-FE8: 18.72um FE3-FE7: 20.16um FE4-FE6: 21.02um FE5: 21.6um Ae: -17.492634 +- 0.197172 [m^2] Beta: 52.097673 +- 1.430265 Gap: 16.295039 +- 0.263495 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 2 (System I) Spot X (contact) Ref: FE1 line FE1-FE9: 14.4um (ref) FE2-FE8: 18.72um FE3-FE7: 20.16um FE4-FE6: 21.02um FE5: 21.6um Ae: -21.272344 +- 0.475360 [m^2] Beta: 187.846238 +- 25.210960 Gap: 24.334253 +- 2.640036 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 3 (System I) Spot Y (contact) Ref: FE1 line FE1-FE9: 14.4um (ref) FE2-FE8: 18.72um FE3-FE7: 20.16um FE4-FE6: 21.02um FE5: 21.6um Ae: -20.931524 +- 0.410712 [m^2] Beta: 179.181191 +- 27.160077 Gap: 52.089544 +- 7.476371 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 4 (System II) Spot X (contact) Ref: FE1 line FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Ae: -19.346360 +- 0.258711 [m^2] Beta: 48.162323 +- 1.980266 Gap: 18.733275 +- 0.188822 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 4 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 4 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Small decays in current Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 5 (System II) Spot X (contact) Ref: FE1 line FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Ae: 20.834107 +- 0.172793 [m^2] Beta: 71.436116 +- 2.545026 Gap: 31.020309 +- 0.502765 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 5 (System II) Spot X (contact) Ref: FE1 line FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Ae: 20.834107 +- 0.172793 [m^2] Beta: 71.436116 +- 2.545026 Gap: 31.020309 +- 0.502765 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 5 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um FE1_1 Discontinuity FE3_i have low values FE3_2 has a jump in current Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (System II) Spot Y Ref: FE1 line FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Ae: 22.404080 +- 0.195159 [m^2] Beta: 299.118793 +- 50.173043 Gap: 239.621151 +- 38.296567 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (System II) Spot Y Ref: FE1 line FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Ae: 22.404080 +- 0.195159 [m^2] Beta: 299.118793 +- 50.173043 Gap: 239.621151 +- 38.296567 [um] Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um All FE lines have a discontinuity at 1.6E-9 A Only in this spot Impurity? 1.6E-9 A Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Data series 6 (Cont’d) FE1-FE6: 18.82um (ref) FE2-FE5: 22.48um FE3-FE4: 29.71um FE7-FE9: 15.12um FE8: 11.39um FE8_1 no spread in original graph, but has discontinuities Breakdown 17th August 2010 R. Santiago Kern

Non-Contact Gap Measurement Conclusions: FE characteristics does not yield a realistic gap measurement, with or without going into contact. Parallel dispersion in the FN graph means discontinuities in the I-V characteristics (i.e. Data 6, FE1 and FE8) Breakdown 17th August 2010 R. Santiago Kern