Diffuse reflectance spectroscopy for in situ process monitoring and control during molecular beam epitaxy growth of InGaAs/AlGaAs pseudomorphic high electron mobility transistors

2000 ◽  
Vol 18 (5) ◽  
pp. 2518 ◽  
Author(s):  
J. E. Guyer ◽  
W. F. Tseng ◽  
J. G. Pellegrino
Keyword(s):  
Molecular Beam ◽  
Diffuse Reflectance Spectroscopy ◽  
High Electron Mobility Transistors ◽  
Molecular Beam Epitaxy Growth ◽  
High Electron ◽  
Monitoring And Control ◽  
Electron Mobility Transistors ◽  
Process 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.

scholarly journals Electric Properties of AlGaN/GaN/Si High Electron Mobility Transistors

2021 ◽  
Author(s):  
H. Mosbahi ◽  
Malek GASSOUMI ◽  
A. Bchetnia ◽  
M.A. Zaidi
Keyword(s):  
Molecular Beam ◽  
Electric Modulus ◽  
Strain Relaxation ◽  
Electrical Conductance ◽  
High Electron Mobility Transistors ◽  
Deep Trap ◽  
High Electron ◽  
Modulus Formalism ◽  
Electron Mobility Transistors ◽  
Barrier Inhomogeneity

Abstract This work investigated the electrical properties in AlGaN/GaN/Si HEMTsgrown by molecular beam epitaxy. The electrical behavior have been investigated using by electric permittivity, modulus formalism and conductance measurements. As has been found from electrical conductance, dispersive behavior is related to barrier inhomogeneity and deep trap in barrier layer. On the other hand, the strain relaxation of charge transport is studied both permittivity and electric modulus formalisms.

Improved device performance of recessed-gate AlGaN/GaN HEMTs using by in-situ N2O radical treatment

2022 ◽  
Author(s):  
Xinchuang Zhang ◽  
Mei Wu ◽  
Bin Hou ◽  
Xuerui Niu ◽  
Hao Lu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Electron Mobility Transistors ◽  
Device Performance ◽  
High Electron ◽  
Electron Mobility Transistors ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Recessed Gate ◽  
Gate Recess

Abstract In this work, the N2O radicals in-situ treatment on gate region has been employed to improve device performance of recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs). The samples after gate recess etching were treated by N2O radicals without physical bombardment. After in-situ treatment (IST) processing, the gate leakage currents decreased by more than one order of magnitude compared to the sample without IST. The fabricated HEMTs with the IST process show a low reverse gate current of 10-9 A/mm, high on/off current ratio of 108, and high fT×Lg of 13.44 GHz·μm. A transmission electron microscope (TEM) imaging illustrates an oxide layer with a thickness of 1.8 nm exists at the AlGaN surface. X-ray photoelectron spectroscopy (XPS) measurement shows that the content of the Al-O and Ga-O bonds elevated after IST, indicating that the Al-N and Ga-N bonds on the AlGaN surface were broken and meanwhile the Al-O and Ga-O bonds formed. The oxide formed by a chemical reaction between radicals and the surface of the AlGaN barrier layer is responsible for improved device characteristics.

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