Analyzing Longitudinal Magnetoresistance Asymmetry to Quantify Doping Gradients: Generalization of the van der Pauw...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Semiconductor Physics

Background:

• Nonuniform doping density in semiconductor samples can lead to longitudinal magnetoresistance asymmetry (LMA).
• LMA is observed in both quantum and classical (Drude) limits under specific conditions.
• Existing methods may not precisely quantify the electron density gradient.

Purpose of the Study:

• To quantitatively deduce the electron density gradient from LMA in the Drude regime.
• To establish a generalized van der Pauw method for density gradient quantification.
• To validate the LMA-derived gradients against local density measurements.

Main Methods:

• Analysis of the current stream function within the van der Pauw measurement geometry.
• Measurement of longitudinal magnetoresistance asymmetry (LMA) under varying magnetic fields.
• Calibration of local carrier densities across a semiconductor wafer.

Main Results:

• The electron density gradient can be quantitatively determined from LMA in the Drude regime.
• The derived gradients show agreement with interpolated local densities.
• The study establishes a novel application of LMA for material characterization.

Conclusions:

• Longitudinal magnetoresistance asymmetry provides a quantitative measure of electron density gradients.
• The van der Pauw method is extended to accurately profile doping nonuniformities.
• This technique offers a valuable tool for semiconductor material analysis and quality control.