Table 2. Microroughness values of uncoated and B4C coated sapphire substrates.
Values measured by white-light interferometry (WLI) and atomic force microscopy (AFM) at HZB.
| Magnification | Uncoated sapphire | B4C coating | |
|---|---|---|---|
| WLI 20× | S q | 0.35–0.42 (nm) r.m.s. | 0.33–0.47 (nm) r.m.s. |
| WLI 40× | S q | 0.18–0.26 (nm) r.m.s. | 0.20–0.26 (nm) r.m.s. |
| AFM 15 × 15 (µm) | S q | 0.12 (nm) r.m.s. | 0.10 (nm) r.m.s. |