Electrical and defect characterization of n-Type GaAs irradiated with α-particles using a van de graaff accelerator and an Am-241 radio-nuclide source

Abstract

Radiation damage effects are studied in OMVPE n‐GaAs for a wide range of alpha (α) particle fluences, using an americium‐241 (Am‐241) radio‐nuclide and a linear van de Graaff accelerator as the particle sources. The samples are irradiated at 300 K, after fabricating palladium Schottky barrier diodes (SBDs) on the 1.2 × 1016 cm−3 Si doped epitaxial layers. The radiation induced defects are characterized using conventional deep level transient spectroscopy (DLTS). A correlation is made between the change in SBD characteristics and the quantity and type of defects introduced during α‐particle irradiation. It is shown that the two parameters most susceptible to this irradiation are the reverse leakage current of the SBDs and the free carrier density of the epilayer. The introduction rate and the “signatures” of the α‐particle irradiation induced defects are calculated and compared to those of similar defects introduced during electron irradiation.

Defect annealing of alpha-particle irradiated n-GaAs

“…An abrupt change in the concentration of defect Ea4 from annealing temperature 463-473 K occurred, the reason for this being unclear at present. The same trend was observed using a different SBD annealed under the exact same conditions and it may possibly be due to the detection of Pal which is situated at approximately the same position in the bandgap as Ea4 and is masked by Ea4 up to 483 K. For the first time the annealing kinetics of the metastable defect Ea3, detected in alpha-particle and protonirradiated n-GaAs is presented [8,10]. To determine the order of the annealing reaction for this defect, (1) was used with a being the order of the reaction.…”

“…Defects Eal, E~2, Ea4 and Ea5 are identical in 307 their DLTS signature and annealing kinetics to the electron-irradiation-induced primary defects El, E2, E3 and E4 [8], whereas Ea3 was not detected after electron irradiation and is believed to be a metastable defect [29]. Figure 1, illustrates the DLTS spectra of the irradiated sample.…”

“…In 1970, Thommen [7] investigated the recovery of lowtemperature electron-irradiation-induced damage in nGaAs, identifying three major irreversible recovery stages (stages I, II and III). In previous studies we have characterised the defects introduced by alpha-particle irradiation at 300 K in n-and p-type GaAs [8,9,10], we have also characterised and presented the annealing kinetics of defects introduced by alpha-particle irradiation in n-GaAs at 15 K [10,11]. This study is a continuation of the work presented by Auret et al [10], where the defects introduced in n-GaAs by alpha-particle and electron irradiation are studied.…”

Effect of 60Co γ-ray irradiation on electrical properties of Ti/Au/GaAs1−xNx Schottky diodes

“…Irradiation is known [38,47,48] to induce displacement of the host atoms to form vacancies, interstitials, and antisite defects and annihilate others defects. Saqri et al [10] , Auret et al [49][50] and Goodman et al [51][52][53][54] found that gamma rays, electron and alpha irradiation enhance intrinsic defects like EL2 , which they assigned to arsenic antisite (As Ga ) or arsenic interstitial.…”

Electrical Characterization Of Defects Introduced During Plasma-Based Processing Of GaAs

“…Its concentration decreased from about 10 14 cm-3 at the interface to 2x1 013 cm-3 at a depth of 0.5 i.tm. The ER9 defect has about the same DLTS "signature" as the P1 defect observed after annealing high energy electron irradiated [23] and alpha-particle bombarded [24] GaAs. The concentration of the only other prominent peak, ERI 0, observed after annealing exhibits the same spatial distribution as the ER9, but its concentration is lower by about a factor of two.…”