论文部分内容阅读
A quasi|thermodynamic model of MOVPE growth of In- x Ga-{1- x }N alloys has been proposed with TMGa, TMIn and ammonia as source materials. In this improved model, the effect of low decomposition rate of ammonia is considered and the number of moles is used to express the mass conservation constraints on element N, H, In and Ga. It is assumed that the alloy was synthesized by the reactions between ammonia and group III elements. The equilibrium partial pressures over the In- x Ga-{1- x }N have been calculated. For the In- x Ca-{1- x } alloys the relationship between the input vapor and the deposited solid composition has been calculated and the results compared with the literature data. The good agreement on the compositions from calculation and the experiment shows that our improved model is suitable for applying to the In- x Ga-{1- x }N alloys grown by MOVPE. It is difficult for In- x Ga-{1- x }N alloy to grow, especially for high|indium alloys, because In- x Ga-{1- x }N is an immiscible alloy and InN has a very high In vapor pressure. It is also shown that gallium has strong tendency of preferential incorporation into the In- x Ga-{1- x }N alloy. In order to enhance the incorporation of indium into the InGaN, we should use the lower growth|temperature,lower reactor pressure, higher input V/III ratio and higher nitrogen fraction in the carrier gas, in addition, the decomposed fraction of ammonia should also be reduced. Indium droplets would be deposed if the growing conditions were not selected properly.
A quasi | thermodynamic model of MOVPE growth of In - x Ga - {1- x } N alloys has been proposed with TMGa, TMIn and ammonia as source materials. In this improved model, the effect of low decomposition rate of ammonia is considered and the number of moles is used to express the mass conservation constraints on element N, H, In and Ga. It is assumed that the alloy was synthesized by the reactions between ammonia and group III elements. For the In - x Ca - {1- x } alloys. The equilibrium partial pressures over the In - x Ga - {1- x } N have been calculated. the relationship between the input vapor and the deposited solid composition has been calculated and the results compared with the literature data. The good agreement on the compositions from calculation and the experiment that that our improved model is suitable for applying to the In - x Ga - {1- x } N alloys grown by MOVPE. It is difficult for In - x Ga - {1- x } N alloy to grow, especially for high | indium alloys, because In - x Ga - {1- x } N is an immiscible alloy and InN has a very high In vapor pressure. It is also shown that gallium has strong tendency of preferential incorporation into the In - x Ga - {1- x } N alloy. In order to enhance the incorporation of indium into the InGaN, we should use the lower growth | temperature, lower reactor pressure, higher input V / III ratio and higher nitrogen fraction in the carrier gas, in addition, the decomposed fraction of ammonia should also be reduced. Indium droplets would be deposed if the growing conditions were not selected properly.