Substitutional Zn in SiGe: Deep-level transient spectroscopy and electron density calculations

Abstract

We investigated by deep-level transient spectroscopy a series of p-Si 1ϪX Ge X samples after in-diffusion of Zn. The measurements reveal two deep hole traps which are attributed to the Zn 0/Ϫ single-and Zn Ϫ/2Ϫ double-acceptor states of isolated Zn atoms on substitutional sites. The corresponding transient peaks are broadened for XϾ0 in comparison to those in pure silicon due to statistical fluctuations of the SiGe alloy composition in the local environment of the Zn atoms. This effect is described quantitatively within the alloy-broadening model which furthermore allows to determine the number of atoms sampled by the defect wave function. The results are compared with ab initio calculations for substitutional Zn in pure Si using the linear muffin-tin orbital method in the atomic-spheres approximation based on the local-density approximation. To model the Ge alloying, we have also studied trigonal pairs of substitutional Zn in Si with a single Ge ligand at different pair distances. From these results, the broadening of the transients can be understood qualitatively.

New Method for Diagnostics of Ion Implantation Induced Charge Carrier Traps in Micro- and Nanoelectronic Devices

“…Filled defect states start emptying, when bias returns back to V R , and that results in a capacitance transient. Filling pulse is applied in a series and the varying capacitance of the diode is given by [16],…”

“…This spectrum of peaks will be similar to a DLTS spectrum (Figure 2) with different DLTS peaks, with peak parameters carrying finger prints of dust species. Once dust mode frequency   and change 0   are measured, further details of experimental and analysis aspects of implementation of this new DLTS can be seen by a selected studies available in the common literature [13][14][15][16][17][18][19].…”

Introduction of deep level impurities, S, Se, and Zn, into Si wafers for high-temperature operation of a Si qubit

“…The group II element Zn and group VI elements S and Se have been introduced into Si by diffusion or ion implantation (I/I), and the formation of deep donors and acceptors have been reported by many groups. [7][8][9][10][11][12][13][14][15][16][17] Note that Zn is a double acceptor, and S and Se are double donors, each of which forms two levels in the Si band gap. However, I/I and postimplantation annealing (PIA) conditions that realize concentration-depth profiles having maximum values at less than 50 nm from the Si wafer surface, which are compatible with Si complementary metal−oxide−semiconductor (CMOS) technology, have not been reported.…”