Deep-Level Defects in High-Dose Proton Implanted and High-Temperature Annealed Silicon

Abstract

We review the principal mechanisms of deep-level defect formation after proton irradiation and subsequent annealing of float zone grown crystalline silicon. Various reaction paths commonly related to vacancy-complexes, interstitial oxygen and hydrogen are discussed. In the experimental part DLTS results of proton-irradiated pn-diode structures are presented. It appears that some detected defects show a thermal stability differing from that reported in literature. Furthermore the metastability of two defects at 300 meV and 418 meV below the conduction band is examined. This behavior commonly designated to a negative-U defect is for the first time reported in a sample annealed at 350° C.

Interaction of low-energy muons with defect profiles in proton-irradiated Si and 4H -SiC

“…Proton-implantation in Si at lower doses is known to produce various defects like vacancy-oxygen (VO) centers, divacancies with several charge states, as well as hydrogenrelated centers near the midgap [13,14]. At higher doses, similar to the ones used here, more extended defects such as dislocations, voids, and even amorphous regions are expected [15][16][17].…”

Metastable Defects in Proton Implanted and Annealed Silicon

“…To overcome the problems occurring when a high number of emission/capture cycles are applied during conventional DLTS (as we recently observed in Ref. [10] where proton implanted and subsequently at 350 °C annealed samples were examined), all following description refer to just one single isothermal cycle as proposed in Ref. [9].…”

“…In the published studies of Tokuda et al [7][8][9]11] the samples were proton implanted under conditions only slightly above fluid nitrogen temperature and subsequently heated up to room temperature, which is not comparable to actual conditions during industrial semiconductor processing. However, from a manufacturing point of view, an increased attention arose from the fact that we could recently detect the metastable defects EM1 and EM2 also in samples processed under conditions suitable for mass production [10]. Thus, the objective of the present study is to introduce a DLTS measurement instruction which is capable of providing further information about the metastable defects EM1 an EM2.…”

“…Due to implantation-induced damage though, also various deep level defects are formed which appear at different implantation-and temperature conditions [3,6]. Among the deep level defects formed after hydrogen implantation doping also two metastable defects were reported which have recently been studied extensively [7][8][9][10]. However, no final consensus has been made on the nature and stability of these defects.…”

The Efficiency of Hydrogen-Doping as a Function of Implantation Temperature

“…In Ref. [13] it is proposed that the high proton dose of several 10 13 cm -2 would promote the formation of V 2 and V 2 O accordingly, whereas at lower doses the A-center (VO) will be formed preferentially. It is argued that at low doses the available O i reservoir is consumed first to from VO centers.…”