Progress in the physical modeling of carrier illumination

Photomodulated Optical Reflectance

2012

In this Chapter, we consider that some perturbation of the free electron distribution N (x, y, z, t), of the free hole distribution P (x, y, z, t) and of the temperature distribution T (x, y, z, t) is present within a silicon sample due to doping and/or optical injection. We investigate how these distributions modify the complex refractive index n(x, y, z, t) of the sample.Without any loss of generality, the perturbed electron, hole and temperature distributions respectively readJ. Bogdanowicz, Photomodulated Optical Reflectance, Springer Theses, 39

Section: Discussionmentioning

confidence: 79%

Theory of Perturbation of the Refractive Index

Photomodulated Optical Reflectance

2012

“…Furthermore, the measurements show that the signal level on the n-type substrates is higher than that on the p-type substrates ͑up to 25% difference͒. This behavior is not expected in theory since the only relevant parameter is the high-injection ambipolar diffusivity 20 which should be independent of the doping type. Most of these differences can however be shown to be due to surface effects ͑Fig.…”

Section: Accuracy and Sensitivitymentioning

confidence: 89%

“…1, which is usually observed on active doping profiles in Si. This asymmetry can be explained by the introduction of carriers into the native oxide ͑charging͒ during the measurement, 19,20 which passivates the surface. In Sec.…”

Section: A Absolute Determination Of Junction Depthsmentioning

confidence: 99%

Nondestructive extraction of junction depths of active doping profiles from photomodulated optical reflectance offset curves

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

Dortu

Clarysse

et al. 2010

Self Cite

The ITRS Roadmap highlights the electrical characterization of the source and drain extension regions as a key challenge for future complimentary-metal-oxide-semiconductor technology. Presently, an accurate determination of the depth of ultrashallow junctions can routinely only be performed by time-consuming and destructive techniques such as secondary ion mass spectrometry ͑SIMS͒. In this work, the authors propose to use the fast and nondestructive photomodulated optical reflectance ͑PMOR͒ technique , as implemented in the Therma-Probe ® ͑TP͒ dopant metrology system, for these purposes. PMOR is a pump-probe technique based on the measurement of the pump-induced modulated change in probe reflectance, i.e., the so-called ͑photo͒ modulated reflectance. In this article, the authors demonstrate that the absolute junction depths of boxlike active dopant structures can be extracted in a very simple and straightforward way from the TP offset curves, which represent the behavior of the modulated reflectance as a function of the pump-probe beam spacing. Although the procedure is based on the insights into the physical behavior of the offset curves, no modeling is involved in the actual extraction process itself. The extracted junction depths are in good correlation with the corresponding junction depths as measured by means of SIMS. The technique has a subnanometer depth sensitivity for depths ranging from 10 to 35 nm with the present Therma-Probe ® 630XP system. The extension of the proposed procedure to the general ultrashallow profiles is also explored and discussed.

“…19, assuming steady-state regime. However, even at low modulation frequency, unlike the plasma which is in phase with the pump ͑ Ӷ 1 at 2 kHz modulation frequency͒, the temperature might suffer from a phase lag with respect to the pump.…”

Section: B Temperature Modelingmentioning

confidence: 99%

“…In previous works, 8,19 the authors have studied the differential reflectance response of uniformly and nonuniformly doped silicon samples, assuming Slotboom's band gap narrowing ͑BGN͒ model and neglecting surface recombinations. In this work, the impact on the differential reflectance of the injection dependent BGN ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Impact of band gap narrowing and surface recombination on photoelectrothermal modulated optical reflectance power curves

Dortu

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

Clarysse

et al. 2008

Self Cite

Photomodulated optical reflectance is a well established technique for surface and near surface characterizations. In this work, the nonlinear behavior of the differential reflectance as a function of the pump irradiance (104–106W∕cm2) is studied on uniformly and nonuniformly (p-n∕p+-p junctions) doped silicon structures, with a particular emphasis on the impact of band gap narrowing (BGN) and of surface recombination velocities (SRVs). We show that the BGN induced by the presence of excess carriers substantially influences the excess carrier profile. We also explain the unexpected shape of power curves on lowly doped substrate by a time-dependent variation of the SRVs during illumination.