Abstract
A new method for accurate in-depth analysis is developed. Since the ion beam is rapidly scanned with triangle waves, a sample surface is evenly etched in a very short time. In this case, the frequency of the triangle wave which is fed to the x-deflector is slightly different from that to the y-deflector and the ratio of these frequencies is held constant. The mass spectrometer can be scanned during ion beam scanning because one-frame scanning time of the ion beam is much shorter than one-peak scanning time of the mass spectrometer. Consequently, concentration profiles of several elements are obtained in one measurement without spoiling the accuracy of in-depth analysis. The accuracy of in-depth analysis by this method is 100Å against 5000Å depth. This value is 8 times smaller than that obtained by conventional ion-beam stopping method. Although ion-etched surface are observed with a scanning electron microscope, a roughness gauge and an optical microscope, unevenness is not identified. This method is applied to practical analyses, i. e. in-depth analyses of aluminum oxide deposited on silicon wafer, copper-diffused gallium arsenide and Se-Te-As compound. The result shows superiority of this method to a conventional one.
