Contactless determination of the carrier mobility sum in silicon wafers using combined photoluminescence and photoconductance measurements

Abstract

A contactless method to determine the carrier mobility sum in silicon wafers, based on a comparison between photoluminescence and photoconductance measurements is presented. The method is applied to monocrystalline silicon wafers and the results are found to be in good agreement with well-established mobility models and another measurement method. The potential of the proposed method to determine the carrier mobility sum of multicrystalline and compensated silicon wafers is then demonstrated.

Contactless determination and parametrization of charge-carrier mobility in silicon as a function of injection level and temperature using time-resolved terahertz spectroscopy

“…From our results, we can conclude that the Klaassen model offers a better description of the experimental data retrieved by TRTS. A conclusion that agrees with non-contact PCD data collected over a narrower injection level window [9,13,29,30]. At present we cannot rationalize the slight deviation between TRTS data and those retrieved by contact methods for concentrations above 1•10 16 cm -3 , in this respect, Klassen suggests that this data might be underestimated by an increase of temperature in the system during the measurements [6].…”

“…To our knowledge this is the first time such correlation is made by TRTS, and over such a large range of injection levels (higher than 1•10 16 cm -3 ) when compared to e.g. photoconductance based non-contact methods [13,29]. Here, we warn the reader that this agreement between TRTS data and the one obtained by contact methods is only reached if diffusion of photogenerated charge carriers from the surface towards the bulk is considered, otherwise bulk charge carrier densities are strongly overestimated (see In order to parametrize the observed experimental results summarized in Figure 2b we fit the data by the classical models developed by Dorkel & Leturcq [5] (dashed line) and Klaassen (solid line) [6,7].…”

“…Over the years all-optical non-contact methods have been employed as alternatives for scrutinizing the charge carrier mobility-charge carrier injection relationship, most notably photoconductance decay (PCD) measurements. This technique is very powerful for estimating the mobility, recombination processes and carrier lifetimes in semiconductors as a function of injection level, however it cannot disentangle (from conductance) the contributions of carrier density and mobility [10][11][12][13] unless it is assisted by a second set of measurements, e.g. time-resolved photoluminescence (TRPL) [13].…”

“…This technique is very powerful for estimating the mobility, recombination processes and carrier lifetimes in semiconductors as a function of injection level, however it cannot disentangle (from conductance) the contributions of carrier density and mobility [10][11][12][13] unless it is assisted by a second set of measurements, e.g. time-resolved photoluminescence (TRPL) [13]. Furthermore, PCD techniques are often able to monitor a relatively narrow range of injection levels (i.e.…”

Measurement and Parameterization of Carrier Mobility Sum in Silicon as a Function of Doping, Temperature and Injection Level

“…However, data for the electron and hole mobility sum as a function of excess carrier density available to date have only been measured at room temperature [9]- [12]. Experimental evidence on the simultaneous impact of excess carrier injection and temperature does not exist, to our knowledge.…”