1. k-Space Associates, Inc. kSA BandiT: Band-edge Thermometry

2. k-Space Associates, Inc. Band-edge Thermometry Principles Semiconductors: transparent for hν = E g Semiconductors: as substrate temperature increases, E g ↓ and λ g ↑ Look at diffusely scattered light component– not the specular component. Specularly reflected (front surface) light does not interact with the wafer.

3. k-Space Associates, Inc.  Pyrometers: Typically inaccurate or no measurement below 400-450 o C Potential interference from stray IR (esp. at low T s ), internal reflections (heterojunctions), coated view ports Absolute temperature calibration from machine to machine is difficult  E g thermometers: Need good light collection & detection system Need good normalization & fitting software Absorbing over layers limit thickness for temperature measurement Band-edge Thermometry vs. Pyrometers

4. k-Space Associates, Inc. State-of-the-art solid state spectrometer - 1000x more sensitivity and no moving parts (longer lifetime, no need for constant recalibration) Excellent S/N without a chopper Efficient collection optics Powerful software and full software development team Operates in either transmission or reflection mode Single USB connection to laptop computer Full technical service and support kSA BandiT vs. Competitor Instruments

5. k-Space Associates, Inc. kSA BandiT Product Specifications BandiT System Schematic

6. k-Space Associates, Inc. BandiT Light Source 150W halogen lamp with gold coated parabolic reflector. Light source collimating optics. Real-time output power control via BandiT software. Internal feedback control for stable intensity and spectral output. NOTE: above ~300 o C can use heater as light source kSA BandiT Product Specs. Cont’d

7. k-Space Associates, Inc. BandiT Detector 2-inch collection optics focusing to 400 um fiber. Single-axis gimble mount for radial scanning between inner/outer platen rings Dual fiber with visible laser for easy alignment. kSA BandiT Product Specs. Cont’d

8. k-Space Associates, Inc. kSA BandiT Product Specs. Cont’d  Spectrometer Visible Model (B-VIS): 512x64 element Peltier-cooled CCD array detector Wavelength Range: 380 nm – 1100 nm or custom SiC, ZnTe, ZnSe substrates NIR Model (B-NIR): 128 element InGaAs temperature stabilized photodiode array with on- board interpolation yields 1024 elements Wavelength Range: 875 nm – 1400 nm GaAs, Si, InP substrates

9. k-Space Associates, Inc. kSA BandiT Software Full hardware control and real-time feedback of lamp and spectrometer Powerful, flexible fitting algorithms Ability to store full, partial, or no spectra and temperature data Full analog and digital I/O capability USB interface, runs from a laptop

10. k-Space Associates, Inc. kSA BandiT Performance Specifications Wavelength Ranges:380-1100 nm 1 875-1400 nm 2 Temperature Update Rate:20 Hz typical, 1 Hz minimum Typical Temperature Ranges:ZnSe: RT – 700 °C 1 ZnTe: RT – 700 °C 1 SiC: RT – 700 °C 1 GaAs: RT - 690 °C 2 InP: RT - 650 °C 2 Si: RT – 600 °C 2 Temperature Resolution:0.1 °C Stability:+/- 0.2 °C (4 hours) Accuracy:+/- 2 °C Outputs:Real-time display Thermocouple (selectable) 10V analog (configurable) Inputs:Thermocouple, Analog [1] [1] B-VIS model [2] [2] B-NIR model

11. k-Space Associates, Inc. BandiT Stability Data – GaAs @ 300C

12. k-Space Associates, Inc. kSA BandiT Performance Specs (cont’d) Noise from rotation ~1-2 o C for all size wafers Pyrometer noise typically much worse for ¼ X 3” pieces No interference from: hot sources highly doped epi (2um of GaAs:C, p = 6.5e19/cm 3 ) high-on-low E g growth (AlGaAs/GaAs) Low-on-high E g growth: InGaAs/InP InGaAs strong IR absorber Clean measurement thru ~ 1.2 um of epi (using heater only)

13. k-Space Associates, Inc. kSA BandiT Calibration File Generation material thickness dopant level Calibration depends on:

14. k-Space Associates, Inc. BandiT, TC, and Pyro Measurement Pyro reads high at low temps because substrate is transparent GaAs Oxide Desorption

15. k-Space Associates, Inc. Interference Oscillations Oscillations in temperature

16. k-Space Associates, Inc. Low Temp GaAs Growth Temp increase due to As absorption TC does not see temp rise due to As Absorption

17. k-Space Associates, Inc. BandiT Measurement During Substrate Rotation Spatially Resolved Wafer Temperature Speed of solid state spectrometer provides spatially resolved temperature across all wafers Wafer temperature can vary widely depending on thermal contact with holder Temperature uniformity across each wafer depends on holder mechanism