Investigation of Oxidation Mechanisms in SOI Structures

薄膜绝缘体上硅（SOI）技术在高速低功耗器件中的应用备受关注。通常，SOI器件的制造工艺与传统的散装器件兼容。然而，SOI器件多了一个硅/氧化物界面，并且SOI衬底中的氧化机制和其他过程不一定与本体材料相同。本研究的目的是探讨SOI结构中的氧化机制和界面陷阱特征。首先，提出了一种利用电荷泵送法测量SOI界面陷阱的新技术。由于体区电阻率高，传统的电荷泵送方法不适用于SOI。我们制作了带有本体终端的SOI结构。在我们的新方法中，脉冲电压不仅作用于栅极，而且作用于本体。体脉冲抑制了电荷泵送电流的减小，使我们能够准确地测量SOI器件中的界面陷阱。在此基础上，提出了一种改进的电荷泵送法测量SOI界面陷阱能量分布的新方法。利用上述新技术对SOI结构的氧化机理和界面陷阱特性进行了深入的研究，表明与传统块体材料的界面相比，SOI结构的界面没有退化。

Thin film Silicom-on-Insulator (SOI) technology has attracted much attention for high-speed and low-power device applications. Usually, the process for SOI device fabrication is compatible with conventional bulk devices. However, the SOI device has one more silicon/oxide interfaces and the mechanisms of oxidation and other process in SOI substrates are not necessarily the same as the bulk materials. The purpose of this study is to investigate the oxidation mechanisms and the interface trap characteristics in SOI structures. First, a new technique is developed to measure the interface traps in SOI using charge pumping method. The conventional charge pumping method are not applied to SOI because of high resistivity of body region. We fabricated SOI structures with body terminal. In our new method, the pulse voltage is applied not only to the gate but also the body. The body pulse suppresses the reduction of the charge pumping current and enables us to accurately measure the interface traps in SOI devices. Next, a new technique is also developed to measure the energy distribution of the interface traps in SOI using modified charge pumping method. The oxidation mechanisms and interface trap characteristics are intensively investigated by above mentioned new technique and it is suggested that the interface of SOI structure is not degraded compared with the interfaces in convensional bulk materials.