Double thermal donors in Czochralski‐grown silicon heat‐treated under atmospheric and high hydrostatic pressures

Abstract

The formation kinetics of Thermal Double Donors, a dominant family of thermal donors in Czochralskigrown silicon annealed at T < 600 °C, is studied in detail. A striking enhancement effect of hydrostatic pressures of about 1 GPa on their formation processes, even in a temperature region of thermal instability of these donor centers at about T = 600 °C under normal conditions, is clearly demonstrated. The experimental data obtained in the present work are in agreement with the recent theoretical calculations of oxygen diffusion and agglomeration processes in heat-treated Si.It is well known that oxygen impurity atoms in Czochralski-grown silicon (Cz-Si) being available in concentrations much higher than the oxygen solubility at room temperature are prone to agglomeration upon heating. Heat treatment of Cz-Si at T < 500 °C gives rise to the formation of a family of Thermal Double Donors (TDDs) consisting of more than 16 centres with shallow and deep energy states in the regions between 44 meV and 70 meV and between 100 meV and 150 meV, respectively [1, 2]. The electrical properties of Cz-Si heat treated at T < 500 °C are mainly determined by this family of thermal donors. The characteristic features of oxygen diffusion and agglomeration processes in annealed Cz-Si have recently been reviewed in [3]. Despite a vast amount of information available in the literature the key steps in these processes are still a matter of discussion. Among many well-known factors producing considerable effects on the TDD formation processes, e.g. heat-treatment regimes, the presence of isovalent impurities C and Ge, and so on, the effects of compressive stresses of about 1 GPa leading to enhanced formation of thermal donors in annealed Cz-Si [4,5] are relatively little studied. The purpose of the present work is to study the formation kinetics of TDDs in a more systematic way. This provides a solid basis for computational simulations giving a clue for the complex nature of oxygen aggregates in Si.

Dopant-defect interactions in Ge: Density functional theory calculations

“…Intrinsic point defects such as vacancies (V) or selfinterstitials or impurities such as oxygen can have an important impact on the defect processes of any semiconductor material [22][23][24][25][26][27][28][29][30][31][32][33][34]. A number of studies concern the intrinsic defects in Ge [22][23][24][25][26][27][28].…”

Unified model of diffusion of interstitial oxygen in silicon and germanium crystals

“…For better understanding of oxygen diffusion in silicon crystals the influence of hydrostatic pressure (P) on the diffusion coefficient has been evaluated. This is particularly interesting as the high hydrostatic pressure (HP) has been found to enhance strongly the oxygen agglomeration at elevated temperatures 14 16 an enhancement and in 17 an opposite effect of retardation of oxygen diffusion occurred at high temperatures under HP has been suggested. In experimental studies of agglomeration processes of oxygen in silicon hydrostatic pressure usually reaches 1-1.5 GPa.…”

IR studies of the oxygen and carbon precipitation processes in electron irradiated tin-doped silicon

“…Isovalent dopants due to their larger size introduce stains in the Si lattice which affect the O and C aggregation processes. Notably, the application of high hydrostatic stress has been determined [68,69] to have also a significant effect on the O agglomeration processes and comparison of the relative results would enhance our understanding of the two phenomena.…”