Hamburg 2001 – scientific programme

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HL: Halbleiterphysik

HL 10: Grenz- und Oberfl
ächen

HL 10.11: Talk

Monday, March 26, 2001, 18:00–18:15, S16

Inspection of surface roughness of semiconductor materials and influence on surface acoustic wave dispersion — •Colm Flannery and Hartmut von Kiedrowski — Paul-Drude-Institut fuer Festkoerperelektronik, Berlin

The effect of surface roughness on adhesion properties of films and interfaces and on performance of sensors and transducers is known to be of key importance. Therefore it is of the utmost importance to be able to measure this quantity and to predict the perturbing effects different roughness levels may cause. Roughness is known to affect the propagation of surface acoustic waves on a material but there is little useful quantitative data on the topic. This work represents an experimental investigation of the effect of surface roughness on laser-generated surface acoustic waves propagating on semiconductor materials (here Silicon and Gallium Arsenide polished/roughened to different roughnesses in the submicron range). The broadband surface acoustic wavepackets (100 MHz centre frequency) become dispersed by the roughness, and the measured degree of dispersion can de directly correlated to the roughness level, (determined by AFM measurements). These results enable remote inspection of surface roughness level with acoustic waves, and provide useful quantitative data to allow estimation of and correction for the effect of roughness on acoustic wave semiconductor devices and acoustic wave inspection techniques.