Limitations in the accuracy of photoconductance-based lifetime measurements

Schüler, Nadine; Anger, Sabrina; Dornich, K.; Niklas, J. R.; Bothe, Karsten

doi:10.1016/j.solmat.2011.11.017

Cited by 10 publications

(5 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As noted above, the loss of the proportionality can be caused by two possible origins: (i) a large Δσ due to a high Δn [19][20][21][22][23][24][25] and (ii) a decrease in μ by electron-hole scattering. 2,26) To identify the dominant origin, we excited carriers in a small area of the sample in µ-PCD measurements.…”

Section: Resultsmentioning

confidence: 99%

“…As discussed in our previous report, 22) the proportionality is lost under a high-injection condition because of two origins: (i) the loss of validity of Eq. ( 1) for large Δσ [19][20][21][22][23][24][25] and (ii) the decrease in μ by electron-hole scattering. 2,26) Origin (i) is due to the fact that ΔP is not a simple function of Δσ.…”

Section: Introductionmentioning

confidence: 99%

“…The change in reflectivity can be considered to be proportional to Δσ only when Δσ is small enough that the higher-order terms of its Taylor series can be neglected (Δσ ≪ σ). [21][22][23][24][25] Therefore, a high Δn induces a large Δσ and a nonconstant A in Eq. ( 1), resulting in nonlinear dependence of ΔP on Δn.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microwave reflectivity from 4H-SiC under a high-injection condition: impacts of electron–hole scattering

Kato

Mori

Ichimura

2015

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

The carrier lifetime and mobility under a high-injection condition are key parameters for the design of bipolar devices. Microwave photoconductivity decay (µ-PCD) is a common method to evaluate the carrier lifetime in silicon carbide (SiC). For accurate evaluation of the carrier lifetime by µ-PCD measurements, we need the proportionality of the microwave reflectivity to the excess carrier concentration. In this study, we observed the loss of the proportionality of µ-PCD signals to the excess carrier concentration under a high-injection condition and we discussed two origins of the loss of proportionality: nonlinear reflection due to a large change in conductivity and mobility reduction by electron-hole scattering. Then we suggested a method to suppress the large change in conductivity and revealed the impacts of electron-hole scattering.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microwave reflectivity from 4H-SiC under a high-injection condition: impacts of electron–hole scattering

Kato

Mori

Ichimura

2015

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…The influence of leakage on the measured effective lifetime is further investigated by means of injection dependent lifetime analysis. Due to observed high lifetimes (see Figure 3), the diffusion lengths, estimated according to Equation (2), strongly exceed the laser spot diameter and it is not possible to calculate the actual injection level [8]. Therefore, throughout this work the effective lifetime is plotted as a function of the optical generation rate instead of the injection level.…”

Section: Resultsmentioning

confidence: 99%

“…After the optical excitation is switched off, excess carriers decay, and cause a decrease of the measured photoconductivity. The lifetime is calculated from the observed exponential decay, whereby linear regression is performed between 75% and 25% of the signal height (see Figure 1) [8]. Rise and decay of the photoconductivity are measured by microwave absorption, therefore, the wafer to be measured is part of a resonant microwave cavity.…”

Section: Methodsmentioning

confidence: 99%

Minority Carrier Lifetime Measurements for Contactless Oxidation Process Characterization and Furnace Profiling

et al. 2019

View full text Add to dashboard Cite

Contactless minority carrier lifetime (lifetime) measurements by means of microwave detected photoconductivity are employed for oxidation process characterization and furnace profiling. Characterization is performed on oxidized float zone substrates with high resistivity and outstanding bulk quality, suggesting that the measured effective lifetime is strongly dominated by interface recombination and therefore reflects the oxide quality. The applied approach requires neither test structures nor time consuming measurements and is therefore of particular interest if high throughput is required. The method is used to investigate the impact of oxidation furnace leakage as well as to analyze the oxidation homogeneity across a horizontal oxidation furnace. For comparison, capacitance-voltage measurements are conducted to characterize the oxide properties. It is found that any type of furnace leakage, which induces fixed oxide charges as well as interface states, has a heavy impact on the measured effective lifetime, especially on the shape of generation rate dependent lifetime curves. Furthermore, a distinct lifetime decrease towards the tube door of the oxidation furnace could be observed. The latter is even detectable in an ideal oxidation process, generating high quality oxides. Besides plain equipment characterization, the presented approach is suitable to optimize the oxidation process itself regarding different parameters like temperature, gas flow, pressure, or process time.

show abstract

Fast, high resolution, inline contactless electrical semiconductor characterization for photovoltaic applications by microwave detected photoconductivity

Dornich

Schüler

Berger

et al. 2013

Materials Science and Engineering: B

View full text Add to dashboard Cite

Limitations in the accuracy of photoconductance-based lifetime measurements

Cited by 10 publications

References 18 publications

Microwave reflectivity from 4H-SiC under a high-injection condition: impacts of electron–hole scattering

Microwave reflectivity from 4H-SiC under a high-injection condition: impacts of electron–hole scattering

Minority Carrier Lifetime Measurements for Contactless Oxidation Process Characterization and Furnace Profiling

Fast, high resolution, inline contactless electrical semiconductor characterization for photovoltaic applications by microwave detected photoconductivity

Contact Info

Product

Resources

About