DLTS of the third acceptor level of substitutional copper in germanium

Abstract

DLTS results of the third acceptor level of substitutional copper in n-type germanium are presented for the first time. Accurate determination of the signature and the temperature dependence of the electron capture cross section yields an energy level of E, -0.26 eV in agreement with the Hall effect. It is shown that two DLTS bands attributed in the literature to the third copper level should correspond to other defects.

Direct estimation of capture cross sections in the presence of slow capture: application to the identification of quenched-in deep-level defects in Ge

“…For this reason, including the independently measured capture cross section (via pulse width variation experiments) in the comparison may be very helpful, and we will do this here wherever possible. In Table II our spectroscopic results for levels H1, H4 and E1 are compared with literature data for the three Cu s levels in Ge, intentionally doped with Cu [40,41]. The resemblance is striking, especially for the capture cross sections and for the activation energies after PF correction.…”

Electronic properties of manganese impurities in germanium

“…The positions of the three peaks are nearly independent of the electric field. Since in the p-type specimen contamination of Cu and Ni [19,20] was present, for comparison a second DLTS measurement was performed on the same sample, but now in between two Mn-dots (p-Ge:REF in figure 1(b)). It can be seen that the Cu and Ni contamination is present in both measurements, while two peaks (Mn-H1 and Mn-H2) are only present under the Mn dot.…”

“…[8][9][10][11][12][13] In view of the above-mentioned applications, it is rather surprising that Mn-related defects in Ge have so-far not been studied with DLTS. The present knowledge of Mn-defect levels in Ge relies on temperature-dependent resistivity measurements by Woodbury and Tyler, [14] performed on Ge crystals doped with Mn in the melt.…”

Optical deep level transient spectroscopy of minority carrier traps in n-type high-purity germanium

“…It was assumed that the negative peak was due to the triply ionized copper acceptor ͑Cu s 2Ϫ/3Ϫ level͒. Optical deep level transient spectroscopy ͑ODLTS͒ with illumination through a semitransparent Schottky barrier was applied by Clauws et al 11 to detect in-diffused copper defects in moderately doped n-type germanium (N Sb ϭ7ϫ10 13 cm Ϫ3 ). The experiments revealed a majority band ͑electron trap͒ around 180 K and a minority band ͑hole trap͒ around 150 K ͑for window ϭ3.7 ms͒.…”

“…The fact that the electron trap around 180 K is not observed as a majority trap in DLTS of n-type HP germanium is readily explained from the electron capture cross section n (Cu s 2Ϫ ) of the order of 10 Ϫ19 cm 2 , yielding an extremely small capture rate with the electron densities available in a HP sample. 3,11 As a consequence, substitutional copper impurities, if present, would escape detection in conventional DLTS of n-type HP germanium. The situation should be more favorable for detection of the copper related hole traps all having high hole capture cross sections, 3 when sufficient hole injection can be provided.…”