Liquid nitrogen flowrate alarm system for MBE

Liquid nitrogen is very important for MBE system. Most MBE systems use the liquid nitrogen to absorb the impurity molecules. If MBE cryoshroud is lack of liquid nitrogen, the pressure of the growth chamber will grow. This will affect the film quality. But too much liquid nitrogen is a waste. We have developed a liquid nitrogen flowrate alarm system to monitor the liquid nitrogen status in MBE cryoshroud. In this method, a temperature sensor is placed at the end of the cryoshroud. The temperature varies with changing of the liquid nitrogen status in cryoshroud. If the liquid nitrogen level in the cryoshroud is too low or too high, the LNFA will send out an alarm to warn the user to adjust the liquid nitrogen flowrate. In our experiments, we found this method works well, and the temperature responds sensitively. With the help of this system, people can view the liquid nitrogen status of the entire growth process. Compare with other method. it is very cheap.

Liquid nitrogen is very important for MBE system. Most MBE systems use the liquid nitrogen to absorb the impurity molecules. If MBE cryoshroud is lack of liquid nitrogen, the pressure of the growth chamber will grow. This will affect the film quality. But too much liquid nitrogen is a waste. We have developed a liquid nitrogen flowrate alarm system to monitor the liquid nitrogen status in MBE cryoshroud. In this method, a temperature sensor is placed at the end of the cryoshroud. The temperature varies with changing of the liquid nitrogen status in cryoshroud. If the liquid nitrogen level in the cryoshroud is too low or too high, the LNFA will send out an alarm to warn the user to adjust the liquid nitrogen flowrate. In our experiments, we found this method works well, and the temperature responds sensitively. With the help of this system, people can view the liquid nitrogen status of the entire growth process. Compare with other method. it is very cheap.

zhangdi于2010-03-29批量导入

zhangdi于2010-03-29批量导入

Chinese Phys Soc.; Shanghai Phys Soc.; Natl Nat Sci Fdn China.; E China Normal Univ, Sch Informat Sci & Technol.; Fudan Univ, Appl Surface Phys Lab.; Natl Lab Infrared Phys.; CAS, Shanghai Inst Tech Phys.; E China Normal Univ, Key Lab Opt & Magnet Resonance Spectroscopy.

Chinese Acad Sci, Inst Semicond, Beijing 100083, Peoples R China

Chinese Phys Soc.; Shanghai Phys Soc.; Natl Nat Sci Fdn China.; E China Normal Univ, Sch Informat Sci & Technol.; Fudan Univ, Appl Surface Phys Lab.; Natl Lab Infrared Phys.; CAS, Shanghai Inst Tech Phys.; E China Normal Univ, Key Lab Opt & Magnet Resonance Spectroscopy.