A Characterization of the Effect of Deposition Temperature on Polysilicon Properties: Morphology, Dopability, Etchability, and Polycide Properties

Abstract

Low pressure chemically vapor deposited polysilicon deposition was studied from 525 to 650~ The silicon appears to be amorphous with a smooth surface up to 550~ and completely crystalline above 600~ The transition region is found to be from 560 to 590~ This transition is marked by sharp crystallographic and resistivity changes. The smooth surface morphology of the amorphous silicon is found to be preserved after POC13 doping and a 1000~ oxidation. The preservation of this smooth morphology is demonstrated to be due to the presence of a native oxide on the surface of the silicon upon exposure to atmosphere. However, an in situ anneal of amorphous silicon at 610~ results in large coarse crystals with rough surface morphology and disparate orientation. The smooth morphology of the 550~ silicon is found to be transmitted through subsequent polycide structure layers. The impact on device reliability is discussed. The amorphous silicon is found to have a higher plasma etch rate than the polysilicon. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.138.73.68 Downloaded on 2014-12-22 to IP

Effects of longitudinal grain boundaries on the performance of MILC-TFTs

“…Large grained poly-Si can be obtained using a variety of techniques: rapid thermal annealing (RTA) [2], excimer laser crystallization (ELC) [3], and SPC [4]. RTA is a hightemperature ( 600 C) process and the resulting films contain high densities of defects.…”

Influences of deposition and crystallization kinetics on the properties of silicon films deposited by low-pressure chemical vapour deposition from silane and disilane

“…For the as-deposited silicon films, a refractive index transition from 4.0 to 3.7 is evidenced for a Vd/Vc value around 1. Since this transition no longer exists after a 15-hours crystallization anneal at 600°C, it should be related to the transition from amorphous silicon (na-Si = 4.00) and polycrystalline silicon (np-Si = 3.70) [14,17,26]. This was confirmed by studying the refractive index variations with the 600°C annealing duration for two amorphous silicon films deposited from silane SiH4…”

Application of Modified Rapid Thermal Annealing to Doped Polycrystalline Si Thin Films Towards Low Temperature Si Transistors.

“…In particular, the LTPS technology has been advanced, based on various crystallization techniques: e.g., sold phase crystallization, excimer laser annealing, rapid thermal annealing, metalinduced crystallization, etc,. [6][7][8][9][10][11][12][13][14] The crystallization techniques can be adapted for activation of ion-doped Si thin films, by making the possibility through slight modifications in processing variables. Ion-doping process accompanies the activation of ions implanted into polycrystalline Si (p-Si) as n-type or p-type.…”