LaB6 Scanning Electron Source Angle Dependent XPS Electrons X-rays Ellipsoidal Monochromator Photoelectrons SCA LaB6 Scanning Electron Source Multi Channel Detector Scanning Input Lens Al Anode 5-Axis Sample Stage The analysis depth is varied by changing the sample tilt angle

Angle Dependent XPS q = 90° q = 10° d = l sin q q d d Analyzer Input Lens Analyzer Input Lens X-ray Beam X-ray Beam e - e - q q = 90° q = 10° q d d d = analysis depth l = electron mean free path q = photoelectron take off angle d = l sin q

ADXPS Profile of the Native Oxide on a Si Wafer Surface Chemical Composition Atomic Concentration Profile 280 285 290 295 2 4 6 500 1000 1500 Binding Energy (eV) c/s C 1s 525 530 535 540 5 10 15 O 1s x103 95 100 105 110 Si 2p metal oxide Corrected for Take-Off-Angle intensity variation 55 50 O 1s 45 40 35 Si 2p - metal Atomic Concentration (%) 30 25 20 Si 2p - oxide 15 C 1s 10 5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Sine of the Photoelectron Take-off Angle

ADXPS Profile of the Native Oxide on a Si Wafer Surface Chemical Composition Atomic Concentration Profile Curve Fitting Used to Isolate Si Metal and Oxide 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 5 10 15 20 25 30 35 40 45 50 55 sine [toa] Atomic Concentration (%) O 1s C 1s Si 2p - metal Si 2p - oxide 92 94 96 98 100 102 104 106 108 110 112 500 1000 1500 2000 2500 3000 3500 4000 Binding Energy (eV) c/s Pos. Chem. State 99.51 Si 2p3 metal 100.11 Si 2p1 metal 103.36 Si 2p oxide Si 2p

Interpretation of ADXPS Profiles Using a Stratification Algorithm The stratification algorithm requires peak intensity data from two or more take off angles. The minimum data set should include a high and low take off angle. Estimation of layer order The peak intensity ratios of all peaks are compared between all the measured take off angles. The number of layers and layer order is based on the correlation of peak intensity ratios. Estimation of film thickness and composition The peak intensities measured at the high take off angle and the layer order information are used to calculate layer thickness and composition. The algorithm is useful for qualitative sample to sample comparisons

Assumptions and Limitations of the Stratification Algorithm Stratification model assumptions Individual layers are continuous and uniform in thickness Individual layers are uniform in composition Interfaces are abrupt Stratification model limitations Generic electron mean free paths are applied for thickness calculations Since the model is not calibrated for the sample being measured, the absolute layer thicknesses may contain systematic error If the actual sample composition violates any of the assumptions, this will impact the layer detection process, composition, and thickness results

Stratification Algorithm Interpretation of the ADXPS Profile of the Native Oxide on a Si Wafer Chemical Composition Atomic Concentration Profile Structure Analysis with automatic layer assignment 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 5 10 15 20 25 30 35 40 45 50 55 sine [toa] Atomic Concentration (%) O 1s C 1s Si 2p - metal Si 2p - oxide Structure Description -2.5 -2 -1.5 -1 -0.5 Depth (nm) C 1s (100.0 %) O 1s (67.0 %) Si 2p – oxide (33.0 %) Si2p – metal (100.0 %) Layer1 Layer2(2.03 nm) Residue (1.77e-008) Top Layer(0.19 nm)

ADXPS Profile of a Self Assembled Thiol Monolayer on Au 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 10 20 30 40 50 60 sine [toa] Atomic Concentration (%) S 2p O1s Au 4f C 1s (C-C/C-H) C 1s (C-O) Chemical Composition Atomic Concentration Profile 80 85 90 95 5 0.5 1 1.5 2 x 10 Binding Energy (eV) c/s Au4f 525 530 535 540 2000 4000 6000 O1s 280 285 290 295 5000 10000 C1s 155 160 165 170 500 1000 1500 S2p Sample in courtesy of Dr. Sophie Noel Laboratoire de Génie Electrique de Paris URA CNRS Universités Paris

ADXPS Profile of a Self Assembled Thiol Monolayer on Au 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 10 20 30 40 50 60 sine [toa] Atomic Concentration (%) S 2p O1s Au 4f C 1s (C-C/C-H) C 1s (C-O) Chemical Composition Atomic Concentration Profile Peak Fit Routine Separating C 1s Chemical States 278 280 282 284 286 288 290 292 294 296 298 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 x 10 4 Binding Energy (eV) c/s Pos. Sep. %Area 284.82 0.00 84.38 C-C/C-H 286.88 2.06 15.62 C-O C 1s

ADXPS Profile of a Self Assembled Thiol Monolayer on Au 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 10 20 30 40 50 60 sine [toa] Atomic Concentration (%) S 2p O1s Au 4f C 1s (C-C/C-H) C 1s (C-O) Chemical Composition Atomic Concentration Profile Structure Analysis with automatic layer assignment Structure Description -2.5 -2 -1.5 -1 -0.5 Depth (nm) O 1s (41.3 %) C 1s C-O (58.7 %) C 1s C-C/C-H (100.0 %) S 2p (100.0 %) Au 4f (100.0 %) Layer1 Layer2(0.11 nm) Layer3(1.58 nm) Top Layer(0.31 nm) Residue (1.18e-010)

HfO2 on Si ADXPS Profile Hf 4f 100 4 80 x 10 O 1s 2.5 60 2 Atomic Concentration (%) 1.5 40 c/s Hf 4f 1 75° 20 45° Si 2p (oxide) 0.5 Si 2p (metal) 30° C 1s 20° 0.4 0.5 0.6 0.7 0.8 0.9 1 30 26 22 18 14 sine [toa] Binding Energy (eV)

HfO2 on Si Structure Analysis 1.11 nm O 1s 71.2% Hf 4f 28.8% -0.5 1.11 nm O 1s 71.2% Hf 4f 28.8% -1 -1.5 -2 Depth (nm) -2.5 2.96 nm O 1s 65.2% Si 2p 13.8% Hf 4f 21.0% -3 -3.5 -4 Si 2p 100% -4.5 1 2 This model was created by a stratification analysis tool in MultiPak. Generic attenuation lengths were used.