Silicon excess and thermal annealing effects on the photoluminescence of SiO2 and silicon rich oxide super enriched with siliscon implantation

Abstract

The off-stoichiometry silicon oxide SiO x (x < 2), known as silicon-rich oxide (SRO), and siliconimplanted thermal silicon oxide (SITO) have shown noticeable photoluminescence (PL) at room temperature. Recently, many efforts to increase the PL in these materials have been made. In our experiments, a considerable increase of the visible emission has been observed when the SRO is super-enriched by silicon implantation. In this experiment, SITO and LPCVD-SRO with different silicon excess, Si implanted and no implanted were studied. Different doses of silicon, and annealing in N 2 at different temperature and times were used. PL response was measured before and after annealing. The emission is explained as the decay between traps in the oxide gap. . Also, some effort to correlate the structural properties and the luminescence of these materials has been made [5,6]. Furthermore, the SRO films have been superenriched with silicon implantation [4] and the luminescent properties have been improved. In this work, SITO films were prepared by silicon thermal oxidation and SRO films were prepared by LPCVD. Some samples were implanted with silicon and subsequent annealing was applied during several time intervals. The PL of all of the samples was measured. The emission was studied as a function of silicon excess and annealing time and temperature. Data analysis was done, and a donor-acceptor electron-decay-like mechanism is used to explain the experimental results.

Optical and electrical properties of silicon rich oxide films for optical sensors

“…Wavelength spectrum from 650 to 800 nm is observed for SRO 10,20,30 . This emission range is characteristic of SRO annealed films on silicon [7]. It is known that thermal annealing, size of Si nanocrystals, and the density of states within the SRO film play a fundamental role in the PL spectra.…”

“…Therefore, we can assume that the absorption and emission processes in SRO films are connected with electrons decay [7] between donor-acceptor pairs localized inside the silicon oxide band gap. Traps inside the band gap can accept or donate one electron turning into donor-acceptor pairs.…”

“…For example, in [7] the SRO radiation properties have been used to extend the detection capability of silicon sensors. However, the photo luminescent mechanisms are not yet completely understood, leading to a field of research with a wide potential.…”

Cathodoluminescence of Silicon Rich Oxide with nitrogen incorporated

“…In most of these applications, compatibility of such materials and the conventional IC's silicon processes is desirable. It has been demonstrated that Silicon Rich Oxide (SRO) films subjected to high-temperature annealing exhibit efficient photoluminescence (PL) [7,8]. Besides, their chemical stability and robustness promise high suitability for integrated electronic and optic device applications.…”

Silicon Rich Oxide with controlled mean size of silicon nanocrystals by deposition in multilayers

“…Among other properties, Si-nCs exhibit photoluminescence in the visible range, attributed to quantum confinement effects and to defects at the interfaces [1]. Additionally, some studies have been performed to use the nCs as charge storing centers in single buried layers [2,3] or superlattices of polysilicon [4].…”