화학증착법에 의한 특수강의 Ti 및 TiN 피복에 관한 연구

Abstract

화학증착법(Chemical Bapor Deposition)을 이용하여 430 Stainless Steel에 Ti 및 TiN를 증착하였다. 온도, 유량, 시간, TiCl₄와 TiI₄분압 등이 증착에 미치는 영향을 조사하였다. 실험결과로부터 증착에 관여하는 율속기구를 규명하였다.

증착속도는 일정한 온?동? 유속하에서는 시간에 따라 직선적으로 증가하였으며 Ti증착시 TiCl₄-H₂혼합기체의 유속이 500ml/min 이하에서는 증착이 확산에 의해 율속되며 그 이상에서는 표면반응에 의해 율속된다. 이때 확산율속단계의 활성화 에너지값은 약 9.12Kcal/mole이며 표면반응율속단계에서는 약 31.2Kcal/mole이었다. 또 TiCl₄를 이용하여 TiN를 증착시킬 경우 1000℃ 이상에서는 표면반응에 의해 율속되고 활성화에너지 값은 약 68.2Kcal/mole이었다.

TiI₄를 사용하여 증착시간, 유령 및 TiI₄분압에 의하여 증착속도에 미치는 영향을 조사한 결과 TiCl₄를 사용한 경우보다 약 2배 정도의 증착속도를 얻을 수 있었으며, 증착층의 형상은 TiCl₄를 사용한 경우는 둥근 돌기모양이었으나 TiI₄를 사용한 경우는 Rectangualr형으로 나타났다.

Ti and TiN was deposited onto 430 stainless steel substrate by means of chemical vapor deposition (CVD) from TiCL₄, H₂and N₂gas mixture.

Effects of temperature, flow rate, time and partial pressure of reacting gas on the deposition were investigated.

Results revealed that the deposition rates of Ti and TiN were increased linearly with respect to reaction time. When the total flow rate was below 500 ml/min. deposition was controlled by diffusion, while above 500ml/min., deposition was controlled by the surface reaction. When the deposition temperature was below 1,100℃, the activation energy for surface reaction controlled mechanism was 31.2Kcal/mole, while the deposition temperature was above 1,100℃, the activation energy for diffusion controlled mechanism was 9.12Kcal/mole.

When titanium nitride was deposited using TiCl₄, the deposition rate was controlled by diffusion above 1,100℃, whereas below 1,000℃, deposition rate controlled by surface reaction. The activation energy for diffusion was 5.6Kcal/mole, while for surface reaction was 68.2Kcal/mole.

When TiI₄was used, the deposition rate was found to be two times as great as the case of TiCl₄.

The morphology of deposited layer revealed globular type in case of TiCl₄gas mixture whereas in case of TiI₄, the morphology showed rectangualr type deposits.

Ti and TiN was deposited onto 430 stainless steel substrate by means of chemical vapor deposition (CVD) from TiCL₄, H₂and N₂gas mixture.

Effects of temperature, flow rate, time and partial pressure of reacting gas on the deposition were investigated.

Results revealed that the deposition rates of Ti and TiN were increased linearly with respect to reaction time. When the total flow rate was below 500 ml/min. deposition was controlled by diffusion, while above 500ml/min., deposition was controlled by the surface reaction. When the deposition temperature was below 1,100℃, the activation energy for surface reaction controlled mechanism was 31.2Kcal/mole, while the deposition temperature was above 1,100℃, the activation energy for diffusion controlled mechanism was 9.12Kcal/mole.

When titanium nitride was deposited using TiCl₄, the deposition rate was controlled by diffusion above 1,100℃, whereas below 1,000℃, deposition rate controlled by surface reaction. The activation energy for diffusion was 5.6Kcal/mole, while for surface reaction was 68.2Kcal/mole.

When TiI₄was used, the deposition rate was found to be two times as great as the case of TiCl₄.

The morphology of deposited layer revealed globular type in case of TiCl₄gas mixture whereas in case of TiI₄, the morphology showed rectangualr type deposits.