Low-temperature Pseudo Substrates by Laser Crystallized High Density Plasma Grown amorphous Silicon and Germanium Film

• Main Authors: Liu, Tung-Ming, 劉東閔
• Other Authors: Ahn, Hyeyoung
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/9g5k6b

碩士 === 國立交通大學 === 光電工程研究所 === 102 === In order to meet short, light and portable electronic products versatility features, its microprocessor and memory required in a limited space to achieve high density, high efficiency, low power consumption and many other needs. Therefore, keep challenges the high cost of scaling technology is needed, but the concept of stacked components developed by three-dimensional integrated circuit technology (3D IC) is very important. According to the plan of ITRS, after 2017 accumulating single chip (monolithic) 3D-IC will become a mainstream technology. Accumulate single chip (monolithic) 3D-IC component is superimposed layers, and does not damage the underlying components. Therefore, the upper component must be able to connect with the rear section of wire process (Back End of the Line, BEOL) compatible, which is one of the key technologies to develop a low thermal budget and high crystallinity of the silicon channel layer. We use the (High-density plasma chemical vapor deposition, HDPCVD) to deposit amorphous silicon films with low hydrogen content and has laser crystallization technology to develop high class crystalline epitaxial channel layer, and to achieve in stackable transistors. Although laser crystallization technology developed over the years, but mostly in the furnace tubes with higher temperature deposited amorphous silicon thin film (600℃). Plasma deposition of silicon thin film systems at lower process temperature (<500℃), but higher hydrogen content (over 1%) will lead to hydrogen explosion in laser crystallization process. In this paper, we will optimize the deposition conditions to develop high-quality and low hydrogen content of amorphous silicon film. And develop a stackable poly-silicon thin-film by laser crystallization technology for integration. In this thesis, we use the high-density plasma chemical vapor deposition system and nanosecond green laser peak crystallization technology to produce poly-silicon thin film transistors. Plasma deposit amorphous silicon films are prepared at 500 ℃, and then converted in laser crystallized technique. X-ray diffraction and electron microscopy analysis verified that the poly-silicon film has 0.5μm grain size. This technique combined with low thermal budget has successfully developed stackable poly-silicon thin film transistor and the carrier mobility can up to 55cm2/Vs. The sub-threshold swing can be less than 0.3V/Decade, and the On/Off current ratio can exceed 105. Finally, the amorphous germanium thin film is under study. We use the same way to deposit an acceptable laser crystallized amorphous germanium film, then converted into a poly-germanium thin film. After laser crystallization, the grain size up to 1.74μm. It’s an exciting preliminary result. Because the germanium is an important element of technical options, due to the carrier mobility is higher than silicon two to three times.