摘要
单晶硅阶梯光栅闪耀面表面粗糙度会引起入射光的散射形成杂散光，为获得低杂散光的阶梯光栅槽形，减小单晶硅阶梯光栅闪耀面表面粗糙度显得尤为重要。在单晶硅湿法刻蚀工艺中，阶梯光栅闪耀面表面粗糙度较大的原因是反应生成的氢气易在硅片表面停留，形成虚掩模，阻碍反应的进一步进行。基于超声波空化作用及异丙醇（IPA）增加单晶硅表面润湿性的原理，在单晶硅湿法刻蚀制作阶梯光栅工艺过程中分别利用超声波震荡法及润湿性增强法对所制阶梯光栅闪耀面表面粗糙度进行改善。利用超声波震荡法所制阶梯光栅闪耀面表面粗糙度小于15nm，利用润湿性增强法所制阶梯光栅闪耀面表面粗糙度小于7nm。同时施以超声波震荡法和润湿性增强法，在异丙醇质量分数范围为5％～20％，超声波频率为100kHz，功率范围为30～50W时，所制阶梯光栅闪耀面表面粗糙度小于2nm，而且当异丙醇质量分数为20％、超声波频率为100kHz以及超声波功率为50W时，所制中阶梯光栅闪耀面表面粗糙度达到1nm。实验结果表明，同时施以超声波震荡法及润湿性增强法，并优化实验参数可以制备更低粗糙度的阶梯光栅。
Surface roughness on blaze plane of silicon echelon grating can induce the scattering of incident light, which means that the size of surface roughness is important to the application of echelon grating in spectrometer industry. In order to reduce the scattering light of echelon grating, an important thing is to decrease the surface roughness on blaze plane of echelon grating. In the silicon wet etching process, the pseudo-mask is formed by the hydrogen bubbles generated during the etching process, which causes high surface roughness and poor surface quality. Based upon the ultrasonic cavitation and wettability enhanced by isopropanol （IPA）, ultrasonic vibration and wettability enhancement are used to improve surface quality of echelon grating during silicon wet etching process. The surface roughness is smaller than 15 nm when using ultrasonic vibration and it is smaller than 7 nm when using wettability enhancement. Combining ultrasonic vibration and wettability enhancement, the surface roughness is smaller than 2 nm when the range of IPA mass fraction, ultrasound frequency and power is 5 % -20 %, 100 kHz and 30-50 W, respectively. The surface roughness is equal to 1 nm when the range of mass fraction of IPA and ultrasound power is 20 % and 50 W and the ultrasound frequency is 100 kHz. The experimental results indicate that the combination of ultrasonic vibration, wettability and optimizing of experimental parameters can fabricate the echelon grating with lower surface roughness.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2014年第3期45-51,共7页
Acta Optica Sinica
基金
国家863计划(2010AA1221091001)
国家重大科研装备开发专项(2011YQ120023)
关键词
光栅
湿法刻蚀
表面粗糙度
超声波震荡
润湿性增强
gratings
wet etching
surface roughness
ultrasonic vibration
wettability enhancement
