Characteristics Study Of Thin Film Growth On (001) And (110) Substrates

The thesis is about the computer simulation of early thin film growth on different substrates. It is composed of two parts. On one hand, it is about a new transition from compact island morphology to dendritic morphology; On the other hand, it is the strips'characteristic simulation on Ag(110) and Cu(110) substrates. At first, some study background is introduced in the thesis. The kinds of island morphologies and the differences between homoepitaxial and heteroepitaxial are introduced according to the STM morphologies obtained from experiments. Then the basic theory of thin film growth is given. Two main diffusion mechanism are highlighted in it, one is hop the other is exchange. In order to simulate the realities better, the exchange diffusion mechanism is considered in our two models:the KMC bcc(001) model and the fcc(110) model. The conclusions are as follow:1. A new phenomena that morphology transits from compact island to dendritic island was observed on (110) substrate when flux was above 0.0015ML/s. And the islands decrease with the substrate temperature, increase with the flux in the new phenomena. The required transition temperature from compact island to denditric one increases with the flux.2. On Ag(110) substrate, at low temperatures, small irregular clusters grow. The key factor that controls this transition is the anisotropy of bonds, in-channel bonds are stable while the cross-channel bonds are weak. In the intermediate regime, long monatomic strips in the [110] direction are found. At high temperatures, large two-dimensional compact clusters are obtained. There in-channel bonds can also be broken. In this case, the tendency to form energetically more stable clusters prevails, and two-dimensional compact islands can grow. And the length of the strips increases with the substrate temperature, decreases with flux. The transition temperature from one-dimensional to two-dimensional increases with the flux, decreases with the coverage.3. Because the hop frequency on Cu(110) is higher than Ag(110), it is easier to form strips on Cu(110) substrate. And the transition temperature from one-dimensional to two-dimensional is lower than it on Ag(110) substrate.