稳定自然对流下的温度梯度液相外延

介绍了稳定自然对流下的温度梯度液相外延,稳定自然对流由加在溶液上的水平温差产生,用简化模式计算了该生长的生长速率,计算给出:该生长的生长速率与水平温差的平方根成比例;具体对Ga_0.85Al_0.15AS生长,在本工作给定的条件下,生长速率为稳态扩散理论预示生长速率的1124倍,在大部份生长面积内,外延层的厚度变化小于平均厚度的±10％,设计了稳定自然对流下的温度梯度液相外延装置,用该装置生长了厚Ga_1-xAl_xAs层,实 关键词：

TEMPERATURE GRADIENT LIQUID PHASE EPITAXY UNDER A STEADY NATURAL CONVECTION FLOW

The temperature gradient liquid phase epitaxy under a steady natural convection flow was introduced. The steady natural convection flow was caused by applying a horizontal temperature difference to the growth solution. The growth rate in this process was calculated using a simple model. It was found that the growth rate is directly proportional to the square root of the horizontal temperature difference and for Ga_0.85Al_0.15 As growth under the condition employed in the present work the growth rate is 1124 times as great as that predicted by the steady state diffusion theory and the deviation of epitaxial layer thickness is not more than 10% over the most part of area of growth layer. The experimental growth system designed for the temperature gradient liquid phase epitaxy under a steady natural convection flow was described. This system was used to grow thick Ga_0.85Al_0.15 As layers. The experimental result shows that the observed growth rate is directly proportional to the power 0.45 of the horizontal temperature difference and for Ga_0.85Al_0.15 As growth the observed growth rate is 156 times as great as that predicted by the steady state diffusion theory and is one-eighth as great as that predicted by the convection theory and at a relatively small horizontal temperature difference the deviation of epitaxial layer thickness is in agreement with the calculated value by the convection theory. The calculated growth rate is higher than the observed growth rate. That is attributed to some approximations made and some indefinite parameters used. Owing to an increase in growth rate the present work was able to grew thick Ga_1-xAl_x As layers at the temperature which is 135-210℃ lower than that used for the similar work.