Quantitative determination of electric field strengths within dynamically operated devices using EBIC analysis in the SEM

Abstract

Although electron beam-induced current (EBIC) technique was invented in the seventies, it is still a powerful technique for failure analysis and reliability investigations of modern materials and devices. Time-resolved and stroboscopic microanalyses using sampling Fourier components decomposed by modulated charge carrier excitation are introduced. Quantitative determination of electric field strengths within dynamically operated devices in the scanning electron microscope (SEM) will be demonstrated. This technique allows investigations of diffusion and drift processes and of variations of electric field distributions inside active devices.

Determination of the electric field distribution within multi-quantum-well light emitting diodes by the use of electron beam induced methods

“…The modulus data of the EBIC signal after the cut-off frequency are directionally proportional to the maximum electric field. This proportionality is also described in [1], but the frequency behavior is not discussed there. By using the classical static EBIC technique without chopping of the electron beam, it is not possible to determine the local depletion region capacitance.…”

“…Electron Beam Induced Current (EBIC) microscopy is a proven analysis method using a scanning electron microscope (SEM). Recently it has become possible to determine the electric field strength for the case of dynamically operated devices with EBIC quantitatively [1], while before quantitative results were only possible for steadystate driven devices under avalanche charge multiplication [2] or using recombination velocity modification [3]. However, it is common to all these works that they anticipate within their theoretical treatment the expansion of the depletion region of the device under test (DUT) to be much wider than the dissipation volume of the electron beam.…”

Advanced SEM/SPM microscopy

“…Local electrical device properties, such as minority carrier diffusion length, position of potential barriers, and the geometry of space charge regions inside devices can be determined by steady-state investigations [7]. Quantitative, time-resolved, and stroboscopic microanalyses of electric field strengths within dynamically operated devices can be performed by using periodic excess carrier generation and decomposing EBIC in Fourier components [8]. Unfortunately, the lateral resolution is limited by the energy dissipation volume and the diffusion length of the minority charge carriers and at electric breakdown the method of beam induced currents is unreliable.…”