Carrier lifetime characterization using an optimized free carrier absorption technique

2002 ◽  
Author(s):  
F. Hille ◽  
L. Hoffmann ◽  
H.-J. Schulze ◽  
G. Wachutka
Keyword(s):  
Carrier Lifetime ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Carrier Absorption ◽  
Absorption Technique

Non-Destructive Assessment Of Semiconductor Carrier Lifetime Using Photothermal Radiometry

1996 ◽  
Vol 428 ◽  
Author(s):  
S. Amirhaghi ◽  
A. J. Kenyon ◽  
M. Federighi ◽  
C. W. Pitt
Keyword(s):  
Carrier Lifetime ◽  
Modulation Frequency ◽  
Broad Band ◽  
Free Carrier ◽  
Surface Recombination Velocity ◽  
Free Carrier Absorption ◽  
Ir Radiation ◽  
Important Indicator ◽  
Carrier Absorption ◽  
Non Destructive

AbstractOf crucial importance to all areas of the microelectronics industry is the characterisation of silicon wafer quality. An important indicator of this is carrier lifetime, and a convenient non-destructive method for its measurement is Pholothermal Radiometry. This involves the photo-generation within a semiconductor sample of electron-hole pairs. Periodic generation of carriers leads to modulation of free-carrier absorption of mid-ir radiation provided by a black body source. The fr-radiation detected from the photo-excited region is inversely proportional to the optically induced carrier density. As the modulation frequency is increased, a point is reached at which the photo-generated carriers no longer have sufficient time to decay between pulses. This frequency is dependent on the carrier lifetime. We present a description of the Photothermal Radiometric lifetime scanning instrument built at UCL. This instrument offers an accurate method for producing detailed maps of carrier lifetime across whole or part wafers. The problem of surface-state effects has been addressed by employing a broad-band uv source to optically fill the surface states of the sample under investigation. The instrument is capable of producing maps of lifetime variation with 0.5 mm resolution. Alternatively, for selected points on a wafer, the instrument can generate detailed frequercy scans of free-carrier absorption. From these, it is possible to obtain information on surface recombination velocity and diffusion length.

Optically Detected Temperature Dependences of Carrier Lifetime and Diffusion Coefficient in 4H- and 3C-SiC

2011 ◽  
Vol 679-680 ◽  
pp. 205-208 ◽  
Author(s):  
Jawad ul Hassan ◽  
Patrik Ščajev ◽  
Kęstutis Jarašiūnas ◽  
Peder Bergman
Keyword(s):  
Diffusion Coefficient ◽  
Decay Time ◽  
Carrier Lifetime ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Time Resolved ◽  
Temperature Dependences ◽  
Carrier Absorption ◽  
Time Resolved Photoluminescence ◽  
And Diffusion

Free carrier dynamics has been studied in 4H- and 3C-SiC in a wide temperature range using time-resolved photoluminescence, free carrier absorption, and light induced transient grating techniques. Considerably high carrier lifetime was observed in 3C-SiC epitaxial layers grown on 4H-SiC substrates using hot-wall CVD with respect to previously reported values for 3C-SiC grown either on Si or on 6H-SiC substrates. The temperature dependences of carrier lifetime and diffusion coefficient for 4H- and 3C-SiC were compared. Shorter photoluminescence decay time with respect to free carrier absorption decay time was observed in the same 4H-SiC sample, while these techniques revealed similar trends in the carrier lifetime temperature dependencies. However, the latter dependences for hot-wall CVD-grown 3C layers were found different if measured by time resolved photoluminescence and free carrier absorption techniques.

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