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本文初步研究了在(100)n—GaAs衬底上液相外延生长GaAs外延层厚度与生长Ga溶液厚度、生长时间、初始过冷度、降温速率的关系,以及影响外延层厚度均匀性的因素。实验指出了在GaAs上液相外延生长Ga_(1-x)Al_xAs层,随着Al含量X值的增加在室温下用X射线单晶衍射仪测得的GaAs-Ga_(1-x)Al_xAs系统的晶格失配增加,但是异质结界面附近的失配位错非常小,几乎与X值无关;而在GaAs上生长Ga_(1-x)Al_xAs_(1-y)P_y外延层,可得到室温下晶格失配非常小的GaAs-Ga_(1-x)Al_xAs_(1-y)P_y系统,但是异质结界面附近的失配位错却非常大,在室温下异质结界面是不匹配的。用熔融KOH腐蚀外延层中位错发现,一部分位错是由衬底位错引入的,而大部分位错是在外延过程中引入的。在现有条件下,可以生长出几平方毫米面积较大区域的无位错外延表面,但大部分最终表面层位错密度比衬底位错高几倍或十几倍。
In this paper, the relationship between the thickness of GaAs epitaxial layer grown on (100) n-GaAs substrate and Ga solution thickness, growth time, initial undercooling and cooling rate, and the factors affecting the uniformity of epitaxial layer thickness . The experiment indicates that the GaAs-Ga 1-x Al x AsAs layer is liquid-phase epitaxially grown on GaAs, and the GaAs-Ga 1-x Al x As system is measured by X-ray single crystal diffractometer at room temperature with the increase of X value. However, the dislocation dislocations near the heterojunction interface are very small, almost independent of the X value. However, the Ga_ (1-x) Al_xAs_ (1-y) P_y epitaxial layer can be obtained on GaAs The lattice mismatch of GaAs-Ga 1-x Al x As 1- (1-y) P y at room temperature is very small but the misfit dislocations near the heterojunction interface are very large. The heterojunction interface at room temperature is not matched. Corrosion of the epitaxial layer with molten KOH to dislocate the found that some of the dislocations were introduced by substrate dislocations and most of the dislocations were introduced during epitaxy. Under current conditions, dislocation-free epitaxial surfaces of large area of several square millimeters can be grown, but most of the final surface layer dislocations are several times or ten times more intense than substrate dislocations.