Thermal Chemical Vapor Deposition of Bis(Tertiary-Butylamino)Silane-based Silicon Nitride Thin Films

Abstract

Sub-90 nm device design presents challenges for lowering thermal budget as well as depositing uniform and conformal thin films for front-end-of-line silicon nitride applications. Among other low-temperature precursors for silicon nitride film deposition, bis͑tertiary-butylamino͒silane ͑BTBAS͒ has gained acceptance for critical applications such as spacer. This paper describes BTBAS based silicon nitride film deposition process optimization for spacer and etch stop applications. The single-wafer chamber design can control and tune the film with respect to deposition rate, film composition, wet etch rate, and film mechanical stress by adjustment of process conditions such as temperature, pressure, and gas flow rates. Computational flow and thermal simulations are employed to optimize chamber design to achieve uniform thin films.

An innovative GC-MS, NMR and ESR combined, gas-phase investigation during chemical vapor deposition of silicon oxynitrides films from tris(dimethylsilyl)amine

“…The adsorption mechanism of these molecules from the gas phase onto the substrate is similar to Equation ( 13) and ( 14), but will result in the formation of a silicon oxynitride film in the case of molecules such as 15, containing a Si-N-Si-O-Si-sequence, Equation (15). The first step when 15 is reacting with the substrate is the formation of an O-Si bond (stronger than a N-Si one), which can act as the driving force of the deposition mechanism.…”

“…14 As an example, the case of hexamethyldisilazane ((CH3)3SiNHSi(CH3)3, HMDSz) is noted, a molecule which does not contain Si-H bonds, and for which the lowest reported temperature for deposition of SiNx or SiOxNy films by thermal CVD is 760°C. 13 Contrary to HMDSz, upon addition of Si-H bonds in the precursor molecule, deposition temperatures can be effectively decreased, as illustrated through the bis(tertiary-butylamino)silane (BTBAS) precursor, which contains two Si-H bonds and allows the deposition of SiNx at 600-675°C, 15 with temperatures down to 550°C also being reported. 16 The presence of additional Si-H bonds is thus expected to decrease the minimum deposition temperature even further.…”

“…The analysis of the solid and liquid phases is performed by conventional X-band ESR spectroscopy, using a Bruker Elexsys spectrometer equipped with a high-resolution cavity. 13 C and 14 N(d,p5) 15 N nuclear reactions, respectively, using incident deuterons of 0.9…”

Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: Trends in Deposition Techniques and Related Applications

“…Alternatively, the pre-adsorption reactions in the case of PA-CVD or PE-CVD could produce more active reactant species, leading to higher surface reaction rates at shorter surface diffusion lengths, potentially producing less contaminated SiN x films but with poorer step coverage and lower etch resistance. 107 Although a significant body of research in thermal CVD SiN x can be found in the literature prior to 2010, 73,105,106,[111][112][113][114][115] there are very few recent reports (within the last five years) on the topic, due most likely to the high thermal budget required for dissociation and reaction of the Si and N chemistries, except for 34 included the use of pulsed RF generated by modulating a continuous 200Hz low-frequency wave signal generator with 50% duty cycle in the PE-CVD reaction of SiH 4 and NH 3 at 150…”

Pattern-dependent microloading and step coverage of silicon nitride thin films deposited in a single-wafer thermal chemical vapor deposition chamber

“…The apparent activation energy for the BTBAS-NH 3 reaction in a single-wafer CVD chamber is 2.0 eV. 24 Based on the PLE results of the present study, this reaction is reaction-rate controlled under the process conditions investigated.…”