MICROSCOPY RESEARCH AND TECHNIQUE 25:181-182 zy (1993) IN-SITU HVEM STUDY OF DOPANT DEPENDENT (113)-DEFECT GENERATION IN SILICON DURING 1-MeV ELECTRON IRRADIATION ALBERT ROMANO-RODRIGUEZ* and JAN VANHELLEMONT"" *LCMM, Departament de Fisica Aplicada i Electrbnica, Universitat de Barcelona, Diagonal 647 zy , E- 08028 Barcelona, Spain. **Interuniversity Micro-Electronics Centre (IMEC), Kapeldreef 75, B-3001 Leuven, Belgium. INTRODUCTION By high flux, high energy electron irradiation in the temperature range between 200 and 900K lattice defects with { 113) habit planes are generated in silicon. The required experimental conditions to form ( 113)-defects can easily be obtained by electron irradiation of thin silicon foils in a high voltage transmission electron microscope (HVEM). In this communication, results are presented of an in-situ study of the effect of dopant con- centration profiles on the { 1131-defect generation in silicon, using 1-MeV electron irradiation in a HVEM. The { 113}-defect nucleation and growth is studied as a function of the irradiation condi- tions and of the dopant type and concentration profile. The observations are interpreted on the basis of well-known point defect reactions and are correlated with data obtained on electron irradiated, homogeneously doped silicon by Fedina and Aseev (1990). EXPERIMENTAL n- or p-type, (001) oriented Czochralski grown silicon wafers with heavily doped surface layers are obtained by boron or phosphorus ion implantation followed by a thermal anneal at 900 or 1000°C to restore the implantation damage and to activate the dopants. Some implantations are per- formed through a patterned silicon oxide or polycrystalline silicon mask to study the influence of two dimensional dopant profiles on the electron irradiation induced defect generation. The 1 -MeV electron irradiations are performed using the JEOL1250 microscope of the University of Antwerpen (RUCA). The temperature of irradiation is varied between 300 and 640K and the electron flux ranges from 2>;10'9 to 2x1020cm-2s-1. OBSERVATIONS AND DISCUSSION Low doping case In CZ silicon, which always contains a high concentration of interstitial oxygen ( 1017-1018 cm-3), dominant sinks for vacancies are not only the formation of di-vacancies (VV) but also, and mainly by the formation of vacancy-interstitial oxygen pairs or "A-centres'' (VOi). In CZ substrates with similar oxygen contents and thermal histories, one expects mainly the self-interstitial related reactions and thus also the { 113)-defects to be influenced by the dopant concentration. High doping case A typical result of 1-MeV electron irradiation induced defects at 643K is shown in figure 1 for a boron implanted n-type CZ silicon substrate. It is observed that during the irradiation a very high density of { 113)-defects develops in an area with a boron concentration between 5x10'7 and 5x101* cm-3. Irradiation at lower temperatures (300K or 493K) does not change the position of the irradiation induced defect band and only the nucleation and growth kinetics of the defects are influ- enced. Re-irradiation of the specimen after turning it upside down in the specimen holder leads to a dissolution of the defects (Romano-Rodriguez and Vanhellemont 1992). Fedina and Aseev (1990) demonstrated that the number of { 113)-defects increases with increasing boron concentration, while the growth velocity of the defects and the critical sample thickness, needed to nucleate de- fects, decreases. Received January 13, 1993; accepted January 21, 1993 zyx 0 1993 WILEY-LISS, INC.