Hydrogen-related shallow thermal donors in Czochralski silicon

Abstract

Six shallow donors are shown to form in Gzochralski silicon deliberately doped with hydrogen during the early stages of heat treatment at 350°C. The ground state energies of five of these donors are altered slightly in material doped with deuterium rather than hydrogen, demonstrating the presence of hydrogen in their cores. One of the donors may account for some of the weak IR absorption features detected in as-grown material. The formation of these donors appears to be linked to the generation of the well known oxygen-related double thermal donors and may reflect the partial passivation of these latter defects.

Infrared absorption in silicon from shallow thermal donors incorporating hydrogen and a link to the NL10 paramagnetic resonance spectrum

“…28 The very small shifts observed here are similar in magnitude to those reported for neutron irradiated FZ Si after treatment in a plasma, 22 but they are on average smaller than those (ϳ0.23 cm Ϫ1 ) reported previously by us for precursor related oxygen defects present after short anneals of CZ Si preheat treated in H 2 gas. 23 Nevertheless, the shift ͑0.16 cm Ϫ1 ) reported for line F ͑246.9 cm Ϫ1 ) ͑Ref. 23͒ may be compared with the same value of 0.15 cm Ϫ1 found in the present work ͑Table I͒.…”

“…Yet another series of shallow centers in the same spectral region has been found in CZ Si after heat treatment in hydrogen gas at 1300°C, followed by a quench to room temperature, prior to short anneals at 350°C. 23 The frequencies of the IR lines again were reduced slightly when deuterium was introduced instead of hydrogen, but, as expected, no shifts were found for the TD͑N͒ 0 defects. An important suggestion of this particular work was that the STD͑N͒ centers were partially passivated TD͑N͒ centers that incorporated a single hydrogen atom.…”

“…In our earlier work, 23 several donors were observed in the initial stages of the passivation process that were attributed to partially passivated TD͑1͒ centers with different geometries. It was suggested that the 1s→2 p Ϯ transition of passivated TD͑2͒ should be identified with the line at 246.8 cm Ϫ1 ͑Table I͒ and we use the same labeling here.…”

Thermal donor formation in direct-plasma hydrogenated n-type Czochralski silicon

“…The deficit is a factor of 10, implying that another TD formation mechanism dominates under the investigated experimental conditions. It has been observed in the past that beside OTDs other hydrogen-related TDs could be formed as well [16][17][18]. These give rise to absorption bands in the wave number range 200-300 cm −1 and, thus, correspond to a series of shallow thermal donors, with ionization energies in the interval 25-40 meV.…”

Ultra-Shallow Thermal Donor Formation in Oxygen-Containing Ambient

“…The oxygen impurities diffuse and agglomerate into electrically active defects upon annealing at low temperatures, and at 350 to 550 C the defects formed can be divided into two families; one of double donor character (TDD) [1] and one more shallow family consisting of single donors called the shallow thermal donors (STDs) [2,3,4]. Three different STD defect families have been found, all with energy position 35 to 36 meV below the conduction band edge (E c ), related to oxygen interaction with hydrogen, aluminum, and possibly nitrogen, respectively [5,6]. Nitrogen has long been known to affect the STD formation [3], and therefore observed nitrogen±oxygen (NO) complexes have been suggested to be one STD family [3,7,8,9].…”