离子注入剥离法制备绝缘体上应变硅及其表征

Fabrication of Strained Silicon on the Insulator by the Ion Implantation Cut Process and Its Characterization

基于弛豫锗硅衬底上生长双轴应变硅技术、离子注入工艺以及选择性腐蚀方法,制备了8英寸(1英寸=2.54 cm)双轴张应变的绝缘体上应变硅(sSOI)材料。利用喇曼光谱分析、缺陷优先腐蚀以及透射电子显微镜(TEM)等方法表征了sSOI材料的应变度、缺陷密度以及晶体质量;制备了基于sSOI材料的n型金属-氧化层-半导体场效晶体管(n-MOSFET)以表征其电学性能,同时在相同工艺下制备了基于SOI材料的n-MOSFET器件作对比。结果表明,制备的sSOI材料顶层应变硅薄膜的应变为1.01%,并且在800℃热处理后仍能保持;应变硅薄膜厚度为18 nm,缺陷密度为4.0×104cm-2,具有较高的晶体质量;制备的sSOI n-MOSFET器件的开关电流比(Ion/Ioff)达到108,亚阈值斜率为69.31 mV/dec,相比SOI n-MOSFET,其驱动电流提高了10倍。

Based on the technique of growing the biaxial strained silicon on the relaxed SiGe substrate,the ion implantation process and the method of selective etching,the 8 inches（ 1 inch =2. 54 cm） biaxial tensile strained silicon on the insulator（ sSOI） was fabricated. The strain degree,defect density and crystal quality of sSOI were characterized by Raman spectra analysis, preferential etching technique,transmission electron microscopy（ TEM） and other methods. The n-type metal-oxide-semiconductor field-effect transistors（ n-MOSFETs） were fabricated using the sSOI substrate to characterize the electrical properties. As a comparison,SOI n-MOSFETs were also fabricated by the same process. The Raman spectra show that the strain degree of the top strained silicon film is 1. 01%,which can be maintained even after a thermal process at 800 ℃. The TEM images indicate that the thickness of the top strained silicon film is 18 nm. After carrying out preferential etching,the defect density of sSOI was calculated,which is as low as 4. 0 × 104cm- 2. The superior crystal quality of the strained silicon film is also confirmed by the TEM images. The on and off current ratio（ Ion/Ioff） of the sSOI n-MOSFET reaches to 108,and the subthreshold slope is 69.31 mV/dec. The device drive current of sSOI MOSFET is 10 times higher than that of the SOI n-MOSFET.