Condensation Mechanism for the Formation of Relaxed SiGe Layer Grown-on-Insulator
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1068-C03-18
Condensation Mechanism for the Formation of Relaxed SiGe Layer Grown-on-Insulator Hun-Joo Lee, Gon-Sub Lee, Young-Soo Han, Seuck-Hoon Hong, Tae-Hun Shim, and Jae-Gun Park Nano scale semiconductor Enginnering, Hanyang University, Nano SOI Process Laboratory, Room #101, HIT. Hanyang University 17 Haengdang-dong, Seoungdong-gu, Seoul, 133-791, Korea, Republic of ABSTRACT The use of the condensation method to grow a relaxed SiGe layer-on-insulator (ε-SGOI) for making high-speed complementary metal–oxide–semiconductor field-effect transistors (CMOSFETs) has attracted interest because of its high quality and cost effectiveness. Many reports have presented its superiority in a device performance to bonding and dislocation sink technologies. However, in case of the condensation method, the mechanism by which the method produces ε-SGOI has also not been clearly explained and the surface properties have not been evaluated. Thus, we investigated the condensation mechanism and the effect of temperature in detail by characterizing the surface property and the Ge profile in the SiGe layer. A SiGe layer on silicon-on-insulator layer was epitaxial grown at 550°C, and three oxidation thicknesses at 40, 60, and 90 nm were grown at 950°C. The Ge concentration was increased from 15 to 38.6%, 46.4%, and 63.2%. In the experiment to measure the effect of temperature, the root mean square decreased from 0.175 to 3.412 nm, and the uniformity of Ge improved when the oxidation temperature was increased from 950 to 1100°C. Therefore, our talk will focus on the explanation for the mechanism by which using the condensation method produces ε-SGOI by characterizing the surface property, the thickness of the SiGe, the remaining Si thickness on the insulator, the Ge concentration in the SiGe layer, and the oxidation temperature. INTRODUCTION SiGe-on-insulator (SGOI) is a typical template substrate for strained Si-SOI MOSFET structures, which benefits from both enhanced mobility provided by its strained channels and from the low junction capacitance of its SOI structures [1-2]. In order to fabricate a strained-SOI MOSFET that has high performance, we need to form highly strained Si layers that are free from dislocations and defects on SGOI substrates [3]. To have free of dislocations and no defective wafers, it is also important to know about the condensation mechanism. A condensation mechanism was revealed by using Ge diffusion, relaxation, Ge profile uniformity, the amount of the oxide growth rate (by dislocation generation), and the time it took the Ge profile in the SiGe layer to change [4-5]. We studied the Ge profile and the roughness of the SiGe layer after the oxidation by changing the oxidation time on an ultra thin SOI wafer. Moreover, we also observed the effect of the oxidation temperature [17]. EXPERIMENT A condensation method using Ge diffusion is the best means to significantly reduce the process time compared with the dislocation sink and the bonding methods previously reported [4-10]. Controlling the final concentration
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