An analytical threshold voltage and subthreshold current model for short-channel AlGaAs/GaAs MODFETs

1993 ◽  
Vol 28 (2) ◽  
pp. 180-183 ◽  
Author(s):  
V.K. De ◽  
J.D. Meindl
Keyword(s):  
Threshold Voltage ◽  
Current Model ◽  
Short Channel ◽  
Subthreshold Current

DC Characteristics of Nanometer-Gatelength GaAS Mesfets

1991 ◽  
Vol 240 ◽  
Author(s):  
K. Nummila ◽  
M. Tong ◽  
A. A. Ketterson ◽  
I. Adesida
Keyword(s):  
Buffer Layer ◽  
Threshold Voltage ◽  
Epitaxial Layers ◽  
Short Channel ◽  
Threshold Voltage Shift ◽  
Subthreshold Current ◽  
Dc Characteristics ◽  
Channel Effects ◽  
Gaas Buffer Layer ◽  
Channel Thickness

ABSTRACTHigh-resolution electron-beam lithography has been used to fabricate GaAs MESFETs with gate-lengths ranging from 1 μm down to 30 nm. Devices were fabricated on two MESFET epitaxial layers; one with undoped GaAs-buffer layer while the other had a p- -GaAs-buffer layer. The DC characteristics including transconductance, output conductance, threshold voltage, and subthreshold current of these devices have been measured. Devices on both epitaxial layers exhibited significant short-channel effects. A negative threshold voltage shift and an increase in the subthreshold current were observed. These effects become prominent as the device aspect ratio (gate length/channel thickness) falls below 5. It is shown however that the effects were considerably suppressed in the layer with p- -GaAs buffer due to better confinement of electrons in the channel.

Analysis of an Anomalous Transistor Exhibiting Dual-Vt Characteristics and Its Cause in a 90nm Node CMOS Technology

2012 ◽  
Author(s):  
Yuk L. Tsang ◽  
Xiang D. Wang ◽  
Reyhan Ricklefs ◽  
Jason Goertz
Keyword(s):  
Threshold Voltage ◽  
Electrical Characterization ◽  
Cmos Technology ◽  
Short Channel ◽  
Visual Defect ◽  
Subthreshold Region ◽  
Short Channel Effect ◽  
Channel Effect ◽  
Transistor Model

Abstract In this paper, we report a transistor model that has successfully led to the identification of a non visual defect. This model was based on detailed electrical characterization of a MOS NFET exhibiting a threshold voltage (Vt) of just about 40mv lower than normal. This small Vt delta was based on standard graphical extrapolation method in the usual linear Id-Vg plots. We observed, using a semilog plot, two slopes in the Id-Vg curves with Vt delta magnified significantly in the subthreshold region. The two slopes were attributed to two transistors in parallel with different Vts. We further found that one of the parallel transistors had short channel effect due to a punch-through mechanism. It was proposed and ultimately confirmed the cause was due to a dopant defect using scanning capacitance microscopy (SCM) technique.

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