Formation of Extremely Flat Silicon Oxide/Silicon Interface by the Thermal Oxidation of Hydrogen-Terminated Silicon Surface

为了获得原子平坦的SiO_2/Si界面，研究了氢原子平整的硅表面的氧化过程。研究了预氧化物对氧化物和界面结构的影响，氧化初期的原子尺度氧化过程和SiO_2价带的形成，以及初始表面平整度和平台宽度对界面形成的影响。发现在300℃的大气压下，在干氧中形成的预氧化物，来源于二氧化硅的Si2p光电子谱的宽度在表面附近变窄。这意味着预氧化抑制了氧化层表面附近的应力松弛。通过H_2SO_4和H_2O_2混合溶液中形成的化学氧化物(H_2SO_4氧化物)、热HNO_3中形成的化学氧化物(HNO_3氧化物)和HCI和H_2O_2混合溶液中形成的化学氧化物(HCI氧化物)对SiO_2/Si(111)界面形成的影响发现，氧化反应发生在…此外，H_2SO_4氧化物/Si界面的冶金界面和结构类似于氢端硅表面在300℃的1Torr干氧中氧化形成的SiO_2/Si界面结构。测量了氧化初期SiO_2价带的形成，并从SiH键伸缩振动产生的红外吸收光谱研究了氧化初期表面硅原子的氧化情况。结合X-RYA光电子能谱检测到的界面亚氧化物的形成，将这些实验结果与原子尺度上的模拟氧化过程进行了比较。模拟结果表明，桥氧原子的形成几率取决于与氧原子结合的硅原子的氧化态和成键构型，并且由于在Si(111)表面上局部氧化反应在界面上逐层进行，而不是均匀地进行，所以在Si(100)表面上的氧化比在Si(111)表面上进行得更为均匀。此外，还研究了阶地宽度对SiO_2/Si(111)界面在600-800℃1Torr干氧中氧化过程中SiO_2价带形成初期的影响。较少

The oxidation of atomically flat hydrogen-terminated silicon surfaces were investigated in order to obtain atomically flat SiO2/Si interfaces. The effects of preoxides on the structures of oxides and interfaces, the atomic-scale oxidation process and SiO2 valence band formation at the intial stage of oxidation, and the effects of flatness of initial surface and terrace width on the interface formation were studied. It was found for the preoxides formed in dry oxygen with atmospheric pressure at 300 degrees centigrade that the width of Si2p photoelectron spectrum originating from silicon dioxide decreases near the surface. This implies that the preoxide suppresses the stress relaxation near the oxide-surface. It was found from the effects of chemical oxide formed in a mixed solution of H2SO4 and H2O2 (H2SO4 oxide), that formed in hot HNO3 (HNO3 oxide) and that formed in a mixed solution of HCI and H2O2 (HCI oxide) on SiO2/Si(111) interface formation that the oxidation reaction occurs at … More the metallurgical interface and the structure of H2SO4 oxide/Si interface is comparable to the structure of SiO2/Si interface formed by the oxidation of hydrogen-terminated silicon surface in 1 Torr dry oxygen at 300 degrees centigrade. SiO2 valence band formation at the initial stage of oxidastion was measured and the oxidation of surface-silicon atoms at the initial stage of oxidation was investigated from the measurement of infrared absorption arising from stretching vibration of SiH bonds. These experimental results combined with the formation of suboxides at the interface detected by X-rya photoelectron spectroscopy were compared with the simulated oxidation process on atomic scale. It was found from this simulation that the formation probability of bridging oxygen atoms depends on the oxidation state and bonding configuration of silicon atoms, which combine with oxygen atoms, and the oxidation proceeds more uniformly on Si (100) surface than on Si (111) surface because on Si (111) surface local oxidation reaction proceeds layr by layr at the interface, but does not proceeds uniformly. Furthermore, the initial stage of SiO2 valence band formation at the effect of terrace width on the changes in SiO2/Si (111) interface with progress of oxidation in 1 Torr dry oxygen at 600-800 degrees centigrade were studied. Less