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为了弄清用 Ga/AsGl_3/H_2方法生长的外延层和 GaAs 衬底之间界面处高阻层的形成而进行了试验。外延层在下列条件下生长:(a)改变生长过程中衬底的温度;(b)在生长开始阶段引入过量的砷蒸气。外延层在高砷压下生长时,界面上没有高阻层存在,替代它的是一个非常薄的低阻区。这种现象被定量地解释为是由于砷蒸气压偏离了反应系统的稳态条件。高阻层在不同温度下的霍耳测量结果表明,高阻是由能级距离价带边缘大约为0.5电子伏的深受主所致,并推断与砷空位有关。
Experiments were conducted to understand the formation of a high-resistance layer at the interface between an epitaxial layer grown by the Ga / AsGl_3 / H_2 method and a GaAs substrate. The epitaxial layer is grown under the following conditions: (a) changing the temperature of the substrate during growth; and (b) introducing excess arsenic vapor at the beginning of growth. When the epitaxial layer grows under high arsenic pressure, there is no high resistance layer at the interface. Instead, it is a very thin low resistance area. This phenomenon is quantitatively interpreted as a steady-state condition due to the arsenic vapor pressure deviating from the reaction system. Hall effect measurements of the high resistance layer at different temperatures show that the high resistance is caused by a deep acceptor whose energy level is about 0.5 electron volts away from the edge of the valence band and is inferred to be related to arsenic vacancies.