GaAs(001)表面预粗糙化过程中的临界减慢

Research of critical-slowing-down during the pre-roughness process of GaAs surface

通过对于GaAs表面形貌在特定As BEP(1.33μPa)、不同温度(570,560,550,540和530℃)下相变过程研究,发现随着温度的降低GaAs预粗糙化过程发生了不同程度的迟滞,在温度降至530℃附近时,延迟现象尤其明显,并且当温度远低于530℃时(As BEP 1.33μPa)GaAs表面将不会发生预粗糙转变。采用二维艾辛模型建立方程结合实验数据对这一现象进行理论解释,理论计算出GaAs预粗糙化相变的临界转变温度为529℃,与实验中获得的数据吻合。采用理论上获得的临界转变温度,利用临界减慢理论对实验现象进行了合理的理论解释,认为在特定条件下GaAs表面系统存在预粗糙化临界转变温度,当衬底温度接近这一温度时,临界减慢现象将会发生;当温度低于临界转变温度时,无论延长多少时间表面形貌相变过程将不会发生。

Pre-roughness process of GaAs surface was studied using reflection high energy electron diffraction and scanning tunneling microscopy. We found that there was distinct difference in surface morphology at different temperature（ 570,560,550,540,530 ℃） under a special As BEP（ 1.33 μPa）. With the temperature decreasing,an obvious delay was discovered in pre-roughness process of GaAs surface,and this process should not onset when the temperature below530 ℃. The critical slowing down theory was introduced to explain experimental phenomena and calculated the critical temperature of GaAs（ 001） roughening through the experiment data and the related theoretical model,and this theoretical result（ 529 ℃） was kept with experiment consequence（ 530 ℃）.