Micro-fabrication and hermeticity measurement of alkali-atom vapor cells based on anodic bonding  

作　　者：Lu Zhang Wendong Zhang Shougang Zhang Shubin Yan 张璐;张文栋;张首刚;闫树斌(Science and Technology on Electronic Test and Measurement Laboratory,North University of China,Taiyuan 030051,China;Key Laboratory of Time and Frequency Primary Standards,National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China)

机构地区：[1]Science and Technology on Electronic Test and Measurement Laboratory,North University of China,Taiyuan 030051,China [2]Key Laboratory of Time and Frequency Primary Standards,National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China

出　　处：《Chinese Optics Letters》2019年第10期88-92,共5页中国光学快报（英文版）

基　　金：supported by the National Key Research and Development Program of China(No.2017YFB0503200);the National Natural Science Foundation of China(Nos.61675185 and 61875250);the Natural Science Foundation of Shanxi Province(No.201701D121065)

摘　　要：A vapor cell provides a well-controlled and stable inner atmosphere for atomic sensors,such as atomic gyroscopes,atomic magnetometers,and atomic clocks,and its hermeticity affects the stability and aging of atomic sensors.We present the micro-fabrication of a micro-electromechanical system wafer-level hermit vapor cell based on deep reactive ion etching and vacuum anodic-bonding technology.The anodic-bonding process with the voltage increasing in steps of 200 V had a critical influence on vapor cell hermeticity.Further,the siliconglass bonding surface was experimentally investigated by a scanning electron microscope,which illustrated that there were no visual cracks and defects in the bonding surface.The leak rate was measured using a helium leak detector.The result shows that the vapor cells with different optical cavity lengths comply with the MIL-STD-883E standard(5×10^-8 mbar·L/s).Moreover,D2 absorption spectroscopy was characterized via optical absorption.The bonding strength was determined to be 13 MPa,which further verified the quality of the vapor cells.A vapor cell provides a well-controlled and stable inner atmosphere for atomic sensors, such as atomic gyroscopes, atomic magnetometers, and atomic clocks, and its hermeticity affects the stability and aging of atomic sensors. We present the micro-fabrication of a micro-electromechanical system wafer-level hermit vapor cell based on deep reactive ion etching and vacuum anodic-bonding technology. The anodic-bonding process with the voltage increasing in steps of 200 V had a critical influence on vapor cell hermeticity. Further, the silicon–glass bonding surface was experimentally investigated by a scanning electron microscope, which illustrated that there were no visual cracks and defects in the bonding surface. The leak rate was measured using a helium leak detector. The result shows that the vapor cells with different optical cavity lengths comply with the MIL-STD-883 E standard(5 × 10-8 mbar·L/s). Moreover, D2 absorption spectroscopy was characterized via optical absorption. The bonding strength was determined to be 13 MPa, which further verified the quality of the vapor cells.

关 键 词：BONDING anodic ALKALI 

分 类 号：TG1[金属学及工艺—金属学]