ESR from boron in silicon at zero and small external stress. II. Linewidth and crystal defects

Abstract

Observations of the ESR lineshape of the shallow acceptor centre B in silicon at zero external stress are reported. The broadening of two AM = 1 transitions can be well fitted by a Voigt profile. The Lorentzian part of the fit is shown to behave in full accordance with the theory of strain broadening by point defects. From linewidth measurements for different oxygen and carbon content the elastic strengths of oxygen end carbon in silicon are determined. All obtainable elastic strengths for point defects in silicon are collected. The possibility of determining the total amount of substitutional impurities from the Lorentzian broadening of the AM = 1 transitions is discussed.Es wird uber Untersuchungen der ESR-Linienform des flachen Akzeptors Bor in Silizium bei uniaxialem Druck Null berichtet. Die Verbreiterung von zwei AM = 1-ffbergiingen hnn sehr gut durch ein Voigt-Linienprofil beschrieben werden. Der Lorentz-Anteil des Voigt-Profils verhiilt sich in den Experimenten in voller ffbereinstimmung mit der Theorie der Linienverbreiterung durch Punktdefekte. Aus Messungen der Linienbreite fiir verschiedene Sauerstoff-und Kohlenstoffkonzentrationen werden die Punktdefektstiirken von Sauerstoff und Kohlenstoff in Silizium bestimmt. Punktdefektstiirken von Zentren in Silizium werden zusammengestellt. Es wird eine Moglichkeit diskutiert, aus der Lorentz-Verbreiterung der AM = 1 Obergiinge den Geaamtgehalt an substitutionellen Verunreinigungen zu bestimmen.

Photoluminescence studies of isotopically enriched silicon

“…However, Neubrand's pioneering observation of ESR from A 0 in B doped silicon in the absence of external strain, with doping concentrations ranging from 10 15 to 10 16 cm À3 , introduced a new problem which has remained unresolved until this work [23,24]. After accounting for all of the possible random strain splittings from the known contaminants in the purest, dislocation-free samples, there remained a sample-independent distribution of A 0 splittings whose origin could not be explained.…”

“…The acceptor states and acceptor BE transitions have been studied by a variety of different experimental techniques such as electron spin resonance (ESR) [23,24], thermal conductivity studies [32][33][34], phonon absorption spectroscopy [25][26][27][28][29][30][31]46] and, most recently, by photoluminescence [35][36][37][38][39]. While electron paramagnetic resonance (EPR) was detected for electrons bound to neutral donor impurities (D 0 ) in Si very early in the development of the semiconductor physics [47], careful searches for EPR from holes bound to neutral acceptors (A 0 ) in Si were initially unsuccessful, as summarized by Kohn [48], who was also the first to point out that the problem likely resulted from the four-fold degeneracy of the A 0 ground state.…”

“…The removal of this broadening in fact reveals new fine structure in the boron (B) BE [22]. Furthermore, the small but sample-independent splittings of the neutral acceptor (A 0 ) ground state in natural Si, observed by different experimental techniques [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], was absent in the isotopically pure 28 Si sample. This surprising result suggests that the A 0 splittings in natural Si result from the isotopic disorder [40].…”

Charge-Insensitive Single-Atom Spin-Orbit Qubit in Silicon

“…Here, [58,62,63,78]. The hydrostatic deformation potential a is not needed since it acts on the valence bands with an identity operator.…”

Determination of Stresses in SiSiO2 and Mechanically Affected Si by EPR

“…For silicon, for instance, a considerable rise of sensitivity is possible using the shallow acceptor boron as paramagnetic probe, because the spin-lattice coefficients Gu and G,, are larger compared to the corresponding ones of iron by the factors 156 and 3077, respectively. Because of this high sensitivity to stresses the EPR spectrum of the free acceptor boron can be measured without additional uniaxial pressure only in highly perfect silicon crystals [31]. Small stresses, produced for instance at preparation of the samples or by oxide layers arising during storage of samples a t room temperature, are already sufficient to generate an important broadening of the EPR lines [32].…”