Green Laser Crystallization of a-Si Films Using Preformed a-Si Lines

Abstract

In this work, amorphous silicon films with preformed a-Si lines were crystallized using a diode pumped solid state green laser irradiating at 532 nm. The possibility of controllable formation of grain boundaries was investigated. The crystallization processes in the rapidly melted silicon films were discussed. The influence of the crystallization parameters (i.e., energy density, scan velocity, etc.) and structure type (i.e., with and without preformed lines) on properties of the crystallized films was studied. The laser treatment with an energy density of 1.00 J/cm2 at a laser pulse overlapping of 90% provided the optimal crystallization process with predefined grain boundary location. X-ray diffraction (XRD), SEM and AFM microscopy have been used to characterize the crystallized silicon films.

Electrical Properties of Plasma-Deposited Silicon Oxide Clarified by Chemical Modeling

“…CMOS post-processing and 3D device integration (1)(2)(3)(4). We recently demonstrated TFTs with competitive mobility values, good ring oscillator performance and low off-state currents (6). This competitive TFT performance was among others enabled by the high-quality plasma-deposited SiO 2 , which could be realized having sufficient understanding of the impact of plasma-deposition conditions on film (electrical) properties.…”

“…A very low midgap interface state density of 3⋅10 10 eV -1 ⋅cm -2 was obtained. These films were successfully applied in the fabrication of low-temperature TFTs with a competitive performance (6,9). The purpose of this work is to demonstrate that modeling of gas-phase reactions can contribute significantly to understand properties of films deposited at different deposition conditions.…”

Electrical Properties of Plasma-Deposited Silicon Oxide Clarified by Chemical Modeling

“…CMOS post-processing and 3D device integration. We recently demonstrated that our ICPECVD gate oxides [1], applied to low-temperature TFTs, exhibited competitive mobility values, good ring oscillator performance and low off-state-currents [2]. The competitive TFT performance was among others enabled by the high-quality plasma-deposited SiO 2 , which could be realized having sufficient understanding of the impact of plasma-deposition conditions on film (electrical) properties.…”

Electronic devices fabricated at CMOS backend-compatible temperatures

“…The average energy density in the beam was adjusted by an optical attenuator. The energy density was defined as the total pulse energy divided by the Full-Width Half-Maximum (FWHM) area of the beam [30][31][32].…”

“…Following the sequential lateral solidification approaches using spacers and seeds, we recently proposed a new approach to control the location of grain boundaries [30][31][32], as illustrated in Figure 6.3. An amorphous silicon layer (with typical thickness 50-100 nm common for poly-Si TFTs [130]) is deposited over parallel amorphous silicon lines, oriented in the lasercrystallization direction.…”