Si衬底上3C-SiC异质外延应力的消除

Strain Reducing in 3C-SiC Film Growth on Si Substrate

利用低压化学气相沉积方法在N型Si衬底上异质外延生长3C-SiC薄膜,研究和分析了不同碳化工艺和生长工艺对3C-SiC外延层的影响;探讨了Si衬底3C-SiC异质外延应力的消除机理。通过台阶仪和XRD对不同工艺条件下的外延层质量进行分析,得到最佳工艺条件的碳化温度为1 000℃,碳化时间为5 min,生长温度为1 200℃,生长速度为4μm/h。对最佳工艺条件下得到的外延层的台阶仪分析表明外延层弯曲度仅为5μm/45 mm;而外延层的XRD和AFM分析表明,3μm厚度外延层SiC(111)半高宽为0.15°,表面粗糙度为15.4nm,表明外延层结晶质量良好。

Heteroepitaxial growth of 3C-SiC on n-Si substrates has been performed by low pressure chemical vapor deposition process.The effects of different carbonized conditions and growth conditions on 3C-SiC films are investigated by optical profilometry and X-ray diffraction.The mechanism to reduce the 3C-SiC/Si warfer strain is discussed.The results show that the curvature of the wafer is reduced when the crystalline quality is improved.This can be interpreted that the crystalline quality improvement increases the intrinsic mismatch strain and compensates for the thermoelastic strain,leading to the reduction of the residual strain.The best process condition is： carbonized temperature 1 000 ℃,carbonized time 5min,growth temperature 1 200 ℃,and growth rate 4 μm/h.High quality SiC epilayer has been obtained under the above condition and the epilayer curvature of the epilayer is only 5 μm/45 mm.The full-width at half maximum of the SiC（111） peak is 0.15°.The surface roughness is 15.4 nm.