Interactions of ion-implantation-induced interstitials with boron at high concentrations in silicon

Abstract

Ion implantation of Si (60 keV, 1×1014/cm2) has been used to introduce excess interstitials into silicon predoped with high background concentrations of B, which were varied between 1×1018 and 1×1019/cm3. Following post-implantation annealing at 740 °C for 15 min to allow agglomeration of the available interstitials into elongated {311} defects, the density of the agglomerated interstitials was determined by plan-view transmission electron microscopy observation of the defects. We report a significant reduction in the fraction of excess interstitials trapped in {311} defects as a function of boron concentration, up to nearly complete disappearance of the {311} defects at boron concentrations of 1×1019/cm3. The reduction of the excess interstitial concentration is interpreted in terms of boron-interstitial clustering, and implications for transient-enhanced diffusion of B at high concentrations are discussed.

Mechanisms of boron diffusion in silicon and germanium

“…74 In addition, a proper substitutional B concentration was demonstrated to suppress the typical {311} defects, by a competitive BIC formation. 75 The phenomenon of B-I clustering has a clear negative drawback as far as the dopant activation is concerned, but in addition, it has a weighty effect on the B diffusion process and on its simulation. In fact, B-I clustering affects the migration events not only because diffusing B atoms are trapped and later on de-trapped once BICs dissolve but also for the reason that the Si self-interstitial density is modified during BIC formation and dissolution, by Is hold and release processes from BICs.…”

Direct correlation of R-line luminescence with rod-like defect evolution in ion-implanted and annealed silicon

“…It is possible that the prolonged anneal may lead to a state where the surrounding strain is reduced as the RLDs further develop and is not sufficient to assist exciton recombination at the defect sites. Finally, processes competing with luminescence from {311} defects such as other nonradiative recombination centers associated with irradiation damage 20 , quenching by dopant effects and trapping of impurities at defects 25,26 may play an important role, especially at long annealing times. For example, gettering of (metal) impurities to dislocations has previously been suggested as a possible cause for observed changes in band-edge luminescence.…”

Recoil implantation method for ultrashallow p+/n junction formation

“…The B hump centered in the end-of-range ͑EOR͒ region was observed by many authors, 4,[16][17][18][19][20][21][22] though the microstructure and kinetics of it still remains controversial. [21][22][23][24][25][26] The amorphous/crystalline ͑a/c͒ interfaces predicted by the TA-MIX simulations are also shown in Fig. 5, which are within the vicinity of the B humps respectively.…”