High-quality Si thin film growth on single-crystalline Al203 films

在Si上异质外延生长绝缘层以及在这些绝缘层上连续生长单晶Si是形成绝缘体上硅（SOI）结构的重要方法。我们提出了γ-Al_2 O_3薄膜作为绝缘体材料，并在γ-Al_2 O_3 Si衬底上获得了高质量的薄膜。外延生长的Si/Al_2O_3/Si叠层结构不仅具有蓝宝石上硅（SOS）结构的特点，而且还具有其它应用于微加工技术的传感器件的优点。然而，对于Si/y-Al_2 O_3/Si叠层结构的器件应用，需要提高薄膜的结晶质量和表面平整度。在本研究中，我们报道了在室温下用气体源分子束外延生长Si膜之前，在γ-Al_2 O_3（111）/Si（111）衬底上淀积薄Al层外延生长高结晶质量的Si膜。 ...更多信息 在室温下，γ-Al_2 O_3（111）/Si衬底上的溅射速率为1A μ m/sec。Al薄膜在室温下外延生长。采用Al固体源和N_2O气体分子束外延技术，在Si（111）衬底上，在650 ~ 900 ℃的生长温度下，外延生长了高结晶质量的γ-Al_2O_3薄膜。将衬底暴露于lsccm的Si_2H_6流。Si薄膜的生长速率为400埃/分。在室温下，在Si_2H_6气体源分子束外延生长Si薄膜之前，先在Al_2O_3（111）/Si（111）衬底上淀积薄Al层，生长出非常平整、结晶质量高的外延Si（111）薄膜。外延硅有一个显着改善的结晶质量和表面形貌相比，没有铝预沉积layr生长。对于高质量Si膜的最佳Al厚度为10埃的Al厚度，在800 ℃下Si生长之前，Al沉积表面被改变为Al-O表面（而不是金属Al层）。然而，对于25埃的Al预沉积层，Al-Al键仍然存在。认为Al_2O_3表面发生了改性，从而改善了在Al_2O_3上生长的Si薄膜的结晶质量。少

Heteroepitaxial growth of insulating layrs on Si and the successive growth of a single crystalline Si on those insulating layrs are of great interest in the formation of silicon-on-insulator (SOI) structures. We have proposed gamma-Al_2O_3 films as an insulator material and obtained high quality on layrs of gamma-Al_2O_3 Si substrates. Epitaxially grown Si/Al_2O_3/Si stacked structures have not only the features of silicon-on-sapphire (SOS) but also other advantages for sensor devices using micro machining technology. However, for device applications of the Si/y-Al_2O_3/Si stacked structure, it is necessary to improve the crystalline quality and surface flatness of grown films. In this research, we report the high crystalline quality epitaxial growth of Si films using thin Al layr deposited onto gamma-Al_2O_3 (111) /Si (111) substrates at room temperature, prior to the growth of Si films by gas source MBE.Before the epitaxial growth of Si, Al was evaporated from Knudsen cell at a rate … More of 1A^^ﾟ/sec on the gamma-Al_2O_3 (111) /Si substrate at room temperature. The Al films were grown epitaxially at room temperature. High crystalline quality gamma-Al_2O_3 films were epitaxially grown on Si (111) substrates at growth temperatures from 650 at 900ﾟC by Al solid source and N_2O gas molecular beam epitaxy. The substrates were exposed to a Si_2H_6 flow of lsccm. The grown rate of Si films was 400A^^ﾟ/min. Very flat epitaxial Si (111) films with high crystalline quality were grown using thin Al layrs deposited onto Al_2O_3 (111) /Si (111) substrates at room temperature, prior to the growth of Si films by Si_2H_6 gas source molecular beam epitaxy. The epitaxial Si had a significantly improved crystalline quality and surface morphology comparable to that grown without the Al predeposition layr. For an Al thickness of 10A^^ﾟ, the optimum Al thickness for a high quality Si film, the Al deposited surface was changed to an Al-O surface (rather than a metallic Al layr) just before Si growth at 800ﾟC.However, Al-Al bonds remain for an 25-A^^ﾟ-thick Al predeposition layr. It is believed that a modification of the Al_2O_3 surface occur, which results in improved crystalline quality of Si films grown on the Al_2O_3. Less