Photothermal dynamic elastic bending in a semiconductor circular plate induced by a focused laser beam

Abstract

Abstract. The theoretical models of optically induced elastic bending for a semiconductor circular plate (clamped and simply supported) was derived including both plasmaelastic (PE) and thermoelastic (TE) wave influences. The PE and TE effects versus the modulation frequency of focused laser excitation were analyzed. Obtained results were compared with the optically excited elastic bending produced by homogeneous surface heat source and with experimental measurements. IntroductionPhotoacoustic (PA) and photothermal (PT) measurement techniques are being extensively developed and applied with increased success to the measurement of thermal, optical, electrical, and other related physical properties, as well as for the investigation of subsurface structure and macroscopic defects of various semiconductors and microelectronic and nanoelectronic devices [1][2][3]. During the last ten years, the PA and PT science and technology, together with micro-and nanosystem technologies, had an important role in the development and production of miniature sensors, actuators, resonators and electromechanical parts. The PA and PT effects that lay in the base of PA and PT methods can be important not only for inspection of various semiconductor systems but also as driving mechanisms for micromechanical structures [4]. In both employment of the PA and PT effect, the thermoelastic (TE) deformation and electronic deformation (ED), as a prominent deformation of semiconductor samples and the main drive mechanisms for micromechanical structures, should be investigated. A few authors have been investigated optically induced thermoelastic bending in various threedimensional (3D) and two-dimensional (2D) configuration [5][6][7][8], using tightly focused incident source and developing a new class of PT detecting techniques based on deflection of probe laser beam (for example, thermal mirror PT methods), but they didn't include ED phenomena. The TE and ED phenomena were experimentally and theoretically analyzed in some one-dimensional (1D) and 2D micromechanical structures [9][10][11], assuming non-focused optical source. In this work, the theoretical model including plasmaelastic (PE) and TE waves was developed to obtain the carrier density, the temperature distribution and the response of different deformation component (the dynamic TE and ED bending) in a semiconductor thin circular plate (2D geometry), generated by a tightly focused and intensity-modulated laser beam. This example is important as a model for semiconductor wafers in many PA and PT experimental configuration and as a model of some micromechanical devices.

An investigation on responses of thermoelastic interactions of transversely isotropic thick circular plate due to ring load with memory-dependent derivatives

“…Considering two-temperature thermoelasticity theory in the frequency domain, Lata [8] investigated the thermomechanical interactions in the fractional theory of thermoelasticity on a homogeneous, isotropic thick circular plate. With both plasmaelastic (PE) and thermoelastic (TE) wave impacts, theoretical models of optically induced elastic bending for a semiconductor circular plate (clamped and simply supported) were developed by Galović et al [9]. A modified version of the Mindlin theory of motion is offered by Senjanović et al [10] for rotations and total deflection.…”