TABLE OF CONTENTS Most nitrides can be characterized as high-temperature materials that show high mechanical strength. A wide variety of electronic properties, from superconductors to dielectrics, can be found in various nitrides. McLean and his co-workers performed pioneering works on sputter deposition of TaN films for making highly precise thin-film resistors.[251] They were used in touch-tone telephones at that time.
Nitride thin films are easily prepared by sputtering; the vapor pressure of nitrides is generally so low that composition in sputtered films will scarcely shift due to evaporation of one species. A sintered nitride target is used for sputtering in Ar gas, and a metal target is used for sputtering in a nitride-forming atmosphere.
Titanium nitride, TiN, shows a cubic structure of the NaCl type. Thin films of TiN are prepared by sputtering from a TiN powder target in Ar. Table 5.42 shows typical sputtering conditions for the deposition of TiN thin films. These sputtered films show a crystalline structure even at a low substrate temperature.
| Sputtering conditions | Film properties | |
|---|---|---|
| Sputter system | RF-magnetron | |
| Target | TiN sintered powder (stainless target dish, 100 mm dia, is used for powder target materials) | Polycrystal (cubic) |
| Sputter gas | 4 10 ?2 torr (Ar 6N) | |
| Substrate | Fused quartz | (111) orientation |
| Sputter power | 400 W | d = 4.24 4.25 A |
| Substrate temp. | 500 C | ? = 2 10 ?4 ?cm |
| Growth rate | 1.5 ?m/hr |
Thin...
