Study on Ge surface oxidation processes based on in-situ analysis

ge_2膜对ge_2的脱附是由顶部和底部两个界面分别发生的反应共同引起的，其脱附速率用扩散限制模型来描述。它在薄膜中诱发了与缺氧有关的缺陷，这种缺陷明显表现为子间隙光吸收的增加。通过在GeO_2薄膜上引入帽层或在热处理过程中控制氧分压来抑制缺陷的产生，电特性得到了显著改善。同时还证明了共存的高k材料增强了界面性能的可控性。

The GeO desorption from GeO_2 films on Ge is caused by the combination of two reactions occurring at the top and bottom interfaces, respectively, and the desorption rate is described by the diffusion-limited model through the GeO_2 film. It induces the oxygen-deficiency-related defects in the films, which is clearly detected as the increase of sub-gap photo absorption. The significant improvement of electrical characteristics was demonstrated through the suppression of defect generation by the introduction of a cap layer on top of GeO_2 film, or the control of oxygen partial pressure during the thermal treatment. The enhancement of the controllability of the interface properties by the coexisting high-k materials was also demonstrated.