ELSEVIER . ..s x.x::;; ::~.~.~~~:~~::~~~i~:~.~:~:~‘~:~,::~,:,~ ,,,,,., ‘-:‘y .&y,~.: .. .. .. ;:y,‘,“:” . ..A . . .. . .:.:::~,:~,~.~,~~ii:.:....:.:; .A.. . . . . . . . . . .. . . . . . . . i ‘,ii. :‘. ~ .,_,.,.,.,.. ~) :“~,~~,,~ y. ” ii. ;.+,:<. applied zyxwvutsrqpo surfa c e sc ie nc e Applied Surface Science 99 (1996) 9-14 AES of semi-insulating polycrystalline silicon layers Jozef Liday *, Stanislav Tomek, Juraj Breza zyxwvutsrqponmlkjihgfedcbaZYXWV Microelectronics Department, S~OLYZ~ Technical University. IlkoCoca 3. 812 19 Bratislaca, Slol*akia Received 20 July 1995; accepted 5 November 1995 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSR Abstract The paper deals with evaluation of Auger electron spectra of semi-insulating silicon (SIPOS) layers. We have found that Auger spectra of SIPOS layers can be simulated by a synthesis of SiLVV Auger spectra of Si and SiO, reference samples and of a spectrum of electron energy losses due to transmission of dominant Auger electrons belonging to pure silicon through the phase of SiO,. 1. Introduction Since several decades, Auger electron spec- troscopy (AES) has been a standard method for elemental analysis of solid surfaces and thin films. The accuracy of quantitative AES is remarkably good, especially in the case of homogeneous alloys, thus when the peak shape is not affected by chemical effects [1,2]. Unlike in chemical compounds, in the case of alloys the Auger current needed for quantita- tive evaluation of spectra can be expressed as a height of the Auger peak in a differentiated spec- trum, dN(E)/d zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA E vs. energy E. Elemental composi- tion is then obtained easily by applying the relative sensitivity factors. So as to reach better accuracy, these factors may be corrected depending on the matrix, thus on the atomic density, electron mean free paths, back scattering factors and even on rela- tive sputtering yields. In chemical compounds, when changes in the shape of Auger peaks often occur, this * Corresponding author. Tel.: -i-42-7-791 125; fax: +42-7- 723480: e-mail: liday@utd.elf.stuba.sk. approach is inappropriate and, in general, elemental sensitivity factors determined experimentally on pure elements can not be applied. In such a case, either new elemental sensitivity factors determined on ref- erence samples of similar composition have to be used, or the Auger current must be expressed as the area below the peak in N(E) and, similarly, elemen- tal sensitivity factors must be derived from peak areas in N(E) spectra of pure elements or by calcu- lations. The assessment of the area below the peak spectra is conditioned by background removal. The problems connected with background subtraction and with the accuracy of single terms occurring in the formula for elemental sensitivity factors were dis- cussed and summarized in [l-7]. Typical compounds in which the shapes of Auger spectra are significantly different from those of pure elements are oxides, carbides and nitrides. Because of its extensive application in microelectronics, much attention has been paid to silicon oxide, particularly to ascertaining the stoichiometry of thin films pre- pared by various technologies. The so-called non- saturated SiO, oxides (where x < 21 are in the focus of interest. 0169.4332/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0169-4332(95)00452-l