Download Deep-Level Transient Spectroscopy

Figure 4: The time variation of capacitance as traps empty [12].
S=
−en (T )t2
−en (T )t1
nT
δC
= [ ] [e
−e
]
C0
2n
(10)
where ω0 and ωb are the widths of the depletion region under zero and reverse bias respectively.
The bias voltage is pulsed to the higher V0 value for the filling pulse time tp to fill the traps again and the cycle
is repeated. This allows many readings to be taken to average the signal over.
3.2.2
Calculating trap energy levels and capture cross-sections
Figure 5 shows how the signal changes as a function of temperature when a single trap is present. This occurs
due to the temperature dependence of the emission rate and it is the plot of the DLTS signal as a function of
temperature that forms a DLTS spectrum.
Figure 5: The temperature dependence of the DLTS signal [12].
From equation 10 it is in fact the emission rate that governs what temperature the signal reaches its peak value.
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