TABLE OF CONTENTS Amorphous materials are prepared by the quenching of melts or vapors.[276][277] Table 5.53 summarizes these quenching processes. Among these processes, vapor quenching is achieved by many thin-film deposition processes including vacuum deposition, sputter deposition, and CVD. Thin films of the amorphous phase are deposited at substrate temperatures below the crystallization temperatures of the thin films. Table 5.54 shows the crystallization temperature for various materials. The metals generally show low crystallization temperatures, while compounds such as oxides typically are much higher.[278][279]
| Quenching process | Quenching speed (deg/sec) | |
|---|---|---|
| from melt | annealing | ? 10 -2 10 -5 |
| air-quenching | 10 | |
| liquid-quenching | 10 3 | |
| sputter-quenching | 10 5 | |
| roller-quenching | ? 10 6 10 8 | |
| from vapor | vacuum deposition, CVD | >10 9 |
| sputtering | >10 16 |
| Materials | Crystallization temperature (K) | Materials | Crystallization temperature (K) |
|---|---|---|---|
| V | ? 3 4 | Cr 2O 3 | 718 |
| Cr | ?220 | MgO | 598 |
| Ga | ? 10 60 | NiO | 558 |
| Ge | 743 | Al 2O 3 | 1003 |
| Si | 993 | Fe 2O 3 | 808 |
| Bi | ? 10 30 | GaAs | ~603 |
| Se | ?300 | SiO 2 | 948 |
| Te | ?280 | TiO 2 | 753 |
| Sn-Cu | ?60 | Ta 2O 5 | 1013 |
The crystallization temperature of metals will increase due to the inclusion of residual gas during deposition. For instance, the crystallization temperature of Fe thin films deposited at 10 -12 10 -10 torr is 4 K. The temperature increases to 75 K when the O 2 partial pressure...
