Non-Contact Mapping of Fe Contamination in Oxidized Si Wafers with Sensitivity in Part-Per-Trillion Range

1996 ◽  
Vol 428 ◽  
Author(s):  
Jacek Lagowski ◽  
Piotr Edelman
Keyword(s):  
Minority Carrier ◽  
Diffusion Length ◽  
Gate Oxide ◽  
Atom Fraction ◽  
Minority Carrier Diffusion Length ◽  
Contact Mapping ◽  
The Past ◽  
Recombination Efficiency ◽  
Iron Contamination ◽  
Before And After

AbstractTraces of iron contamination as minute as one part per trillion atom fraction can be detrimental to the gate oxide integrity of the very thin oxides, 10 nm or less, used in the most advanced ICs. Fe contamination monitoring discussed in this paper is done with the surface photovoltage (SPV) technique which measures the minority carrier diffusion length, L, before and after the recombination efficiency of iron is enhanced by optical splitting of the iron-boron pairs. Wafer-scale mapping of iron gives fingerprints of contaminating tools and processes. In this paper, we also present an extension of SPV to oxidized wafers. In the past, such measurements were rendered impossible due to optical interference in the SiO2.The apparatus incorporates a whole wafer, optical Fe activation station and it provides whole wafer maps of Fe in a total time of 6 to 20 minutes per wafer, depending on probing density.

Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

1990 ◽  
Vol 48 (4) ◽  
pp. 744-745
Author(s):  
D.P. Malta ◽  
M.L. Timmons
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Logarithmic Scale ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

Study of the spatial distribution of minority carrier diffusion length in epiplanar detector structures

2015 ◽  
Vol 23 (4) ◽  
Author(s):  
T. Piotrowski ◽  
M. Węgrzecki ◽  
M. Stolarski ◽  
T. Krajewski
Keyword(s):  
Spatial Distribution ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Silicon Detector ◽  
Monochromatic Radiation ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion ◽  
Spot Diameter ◽  
Photoelectric Current ◽  
Effective Carrier

AbstractOne of the key parameters determining detection properties of silicon PIN detector structures (pThe paper presents a method for measuring the spatial distribution of effective carrier diffusion length in silicon detector structures, based on the measurement of photoelectric current of a non-polarised structure illuminated (spot diameter of 250 μm) with monochromatic radiation of two wavelengths λ

scholarly journals Measuring the minority carrier diffusion length in n-GaN using bulk STEM EBIC

2018 ◽  
Vol 24 (S1) ◽  
pp. 1842-1843
Author(s):  
Zoey Warecki ◽  
Vladimir Oleshko ◽  
Kimberlee Celio ◽  
Andrew Armstrong ◽  
Andrew Allerman ◽  
...  
Keyword(s):  
Minority Carrier ◽  
Diffusion Length ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion
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