Polycrystalline silicon

About: Polycrystalline silicon is a research topic. Over the lifetime, 19554 publications have been published within this topic receiving 198222 citations. The topic is also known as: polysilicon & poly-Si.

Deep trench filling method using silicon film deposition and silicon migration

Abstract: A method of filling one or more trenches formed in a silicon substrate includes the steps of forming a thin polycrystalline silicon film in a trench such that the thin polycrystalline silicon film is sufficiently thin so as to not close the trench; forming an amorphous silicon film on thin polycrystalline film and the surface of the substrate and in the trenches; and annealing the amorphous silicon film such that the amorphous silicon layer migrates to fill the trenches to a first level. The deposition and annealing steps are performed in ambient atmospheres having low partial pressures of H 2 O and O 2 , the annealing temperature is higher than the deposition temperature, and the annealing pressure is greater than the deposition pressure.

Self-aligned integrated circuits

Abstract: Semiconductor integrated circuits, including, e.g., field effect transistors and memory cells employing field effect transistors, are formed by providing at a surface of semiconductor substrate a pair of isolation mediums and a plurality of spaced apart conductive lines extending between the isolation mediums. The conductive lines, such as polycrystalline silicon or polysilicon lines, are preferably thermally, chemically or anodically self insulatable in an unmasked batch process step and are made of a material suitable for defining a barrier to a dopant for the semiconductor substrate. Signal or bias voltages are applied to selected or predetermined conductive lines to provide control electrodes or field shields for the transistors. When the substrate has deposited on its surface an insulating medium made of a dual dielectric, such as silicon dioxide-silicon nitride, the dopant may be ion implanted through the insulating medium to form, e.g., the source and drain electrodes of the transistors as defined by the isolation mediums and the conductive lines. Other elements may be added to the structure to form, e.g., a memory cell. By depositing a conductive medium over the insulated conductive lines, the medium may be appropriately etched to provide desired access lines, capacitor electrodes, ground planes or additional field shields for the cells.

Elimination of dehydrogenation step when forming a silicon thin film device by low-temperature laser-annealing

Abstract: Disclosed is a process of forming a silicon thin film used as an active layer of a thin film transistor, which process is improved for enhancing a quality and a productivity of the silicon thin film. At a physical vapor deposition step, an amorphous silicon thin film is physically formed on a substrate in vacuum. Then, at a laser annealing step, directly after formation of the amorphous silicon thin film without the need of dehydrogenation, a laser light is irradiated to the amorphous silicon thin film, to convert the amorphous silicon thin film into a polycrystalline silicon thin film. After that, the polycrystalline silicon thin film thus converted is processed to form a thin film transistor. In the physical vapor deposition step, an amorphous silicon thin film may be formed by sputtering using a target made from a silicon crystal body or a silicon sintered body. In the sputtering, an amorphous silicon thin film can be formed by sputtering using a target previously mixed with an impurity in a desired concentration. By introducing an impurity in the amorphous silicon thin film at the film formation stage, a threshold characteristic of a thin film transistor can be previously controlled.

Arsenic implantation into polycrystalline silicon and diffusion to silicon substrate

Abstract: Arsenic implantation into polycrystalline silicon and drive‐in diffusion to silicon substrate have been investigated by MeV He+ backscattering analysis and also by electrical measurements. The range distributions of arsenic implanted into polycrystalline silicon are well fitted to Gaussian distributions over the energy range 60–350 keV. The measured values of RP and ΔRP are about 10 and 20% larger than the theoretical predictions, respectively. The effective diffusion coefficient of arsenic implanted into polycrystalline silicon is expressed as D=0.63 exp[(−3.22 eV/kT)] and is independent of the arsenic concentration. The drive‐in diffusion of arsenic from the implanted polycrystalline silicon layer into the silicon substrate is significantly affected by the diffusion atmosphere. In the N2 atmosphere, a considerable amount of arsenic atoms diffuses outward to the ambient. The outdiffusion can be suppressed by encapsulation with Si3N4. In the oxidizing atmosphere, arsenic atoms are driven inward by growing...