In situ thickness monitoring and control for highly reproducible growth of distributed Bragg reflectors

1994 ◽  
Vol 12 (2) ◽  
pp. 1221 ◽  
Author(s):  
Y. M. Houng
Keyword(s):  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Monitoring And Control ◽  
And Control

scholarly journals Correlation Between Insulation Resistance and Temperature Measurement Error in Type K and Type N Mineral Insulated, Metal Sheathed Thermocouples

2022 ◽  
Vol 43 (3) ◽  
Author(s):  
Jonathan Pearce ◽  
Declan Tucker ◽  
Carmen García Izquierdo ◽  
Raul Caballero ◽  
Trevor Ford ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Insulation Resistance ◽  
Monitoring And Control ◽  
Type K ◽  
Reference Type ◽  
Process Monitoring And Control ◽  
Resistance Breakdown ◽  
And Control

AbstractMineral insulated, metal sheathed (MI) Type K and Type N thermocouples are widely used in industry for process monitoring and control. One factor that limits their accuracy is the dramatic decrease in the insulation resistance at temperatures above about 600 °C which results in temperature measurement errors due to electrical shunting. In this work the insulation resistance of a cohort of representative MI thermocouples was characterised at temperatures up to 1160 °C, with simultaneous measurements of the error in indicated temperature by in situ comparison with a reference Type R thermocouple. Intriguingly, there appears to be a systematic relationship between the insulation resistance and the error in the indicated temperature. At a given temperature, as the insulation resistance decreases, there is a corresponding increasingly negative error in the temperature measurement. Although the measurements have a relatively large uncertainty (up to about 1 °C in temperature error and up to about 10 % in insulation resistance measurement), the trend is apparent at all temperatures above 600 °C, which suggests that it is real. Furthermore, the correlation disappears at temperatures below about 600 °C, which is consistent with the well-established diminution of insulation resistance breakdown effects below that temperature. This raises the intriguing possibility of using the as-new MI thermocouple calibration as an indicator of insulation resistance breakdown: large deviations of the electromotive force (emf) in the negative direction could indicate a correspondingly low insulation resistance.

Real-time monitoring and control during MBE growth of GaAs/AlGaAs Bragg reflectors using multi-wavelength ellipsometry

1997 ◽  
Vol 44 (1-3) ◽  
pp. 134-138 ◽  
Author(s):  
Blaine Johs ◽  
Craig Herzinger ◽  
Ping He ◽  
Shakil Pittal ◽  
John Woollam ◽  
...  
Keyword(s):  
Real Time ◽  
Bragg Reflectors ◽  
Monitoring And Control ◽  
Real Time Monitoring ◽  
Mbe Growth ◽  
Multi Wavelength ◽  
And Control

In-situ monitoring and control for MOCVD growth of AlGaAs and InGaAs

1997 ◽  
Vol 26 (10) ◽  
pp. 1145-1153 ◽  
Author(s):  
A. Kussmaul ◽  
S. Vernon ◽  
P. C. Colter ◽  
R. Sudharsanan ◽  
A. Mastrovito ◽  
...  
Keyword(s):  
In Situ Monitoring ◽  
Monitoring And Control ◽  
Mocvd Growth ◽  
And Control
Sign in / Sign up

Export Citation Format

Share Document