Temperature dependence of the sticking probability and molecular size of the film growth species in an atmospheric chemical vapor deposition process to form AlN from AlCl3 and NH3

Abstract

The sticking probability and molecular size of the growth species were determined as a function of deposition temperature ranging from 700 to 950 °C, in the AlN films prepared from AlCl3 and NH3. A novel method was developed, that includes the measurement of the film thickness profile on micron-sized trenches and the molecular diffusivity of the growth species. The molecular size was about 1 nm at 700–850 °C and decreased gradually with increasing temperature. The sticking probability increased from 0.02 to 0.5 in the temperature range 700–950 °C and, surprisingly, obeyed the Arrhenius law in spite of this large probability of sticking. The activation energy amounted to 136 kJ/mol.

Atmospheric pressure chemical vapor deposition mechanism of Al2O3 film from AlCl3 and O2

“…At high temperatures ranging from 800 to 950 1C, the size varies from 1.2 to 0.94 nm, which are equivalent to clusters containing 18 and 8 molecules of AlCl 3 , respectively. The cluster size in this study is comparable to that obtained for the CVD of AlN from AlCl 3 and NH 3 [18][19][20].…”

“…The linearity of the semi-logarithmic plot supports this assumption. The relation of the slope (a) of the semi-log plots with the tube diameter (d) can be used to identify the rate-limiting step [18][19][20][21][22]. For example, in Fig.…”

“…Association reactions of the intermediates yield clusters that diffuse to the substrate surface to form the film or serve as nucleus for the formation of particles [23,24]. The Chapman-Enskog equation can be used to estimate the collision diameter or molecular size of the diffusing gaseous species if the diffusivities are known [18][19][20][21][22]25]. Since we have a three-component system involving AlCl 3 , Ar, and O 2 , we employ the Stefan-Maxwell equation [26] in our calculations.…”

Determination of the molecular size of growth species in the AP-MOCVD of ZnO from DEZ and H2O

“…where u is the gas velocity, C is the concentration, and k is the deposition rate constant whose value depends on the ratelimiting step of film growth [16][17][18],…”

“…We have developed a method to estimate the molecular size of the growth species from experimentally obtained diffusivity by analyzing the growth rate profile along the reactor length of simple geometry and well-defined flow [16][17][18]. By using this method, we have obtained the molecular size of the growth species to be about 1 nm (molecular weight of about 460 amu) in the CVD of AlN from AlCl 3 and NH 3 .…”