Monochlorosilane for Low Temperature Silicon Epitaxy

Abstract

Silane (SiH 4 ) and dichlorosilane (DCS) are currently the precursors of choice for Silicon Vapor Phase Epitaxy at low temperatures (T < 1000 C). But device innovation is pushing down process thermal budgets to the extent that it becomes apparent that in the near future poor Si growth rates will become a roadblock for high volume manufacturing. Therefore, new precursors that produce high growth rates at low deposition temperatures (<650 C) are needed for advanced epitaxial applications, such as recessed sour-ce=drain stressors, Metal Oxide Semiconductor (MOS) channels and elevated source=drain structures. The primary objective of this study is to investigate the suitability of monochlorosilane (MCS) for Si epitaxy. It appears that MCS fulfills all the basic criteria, i.e. successful epitaxial growth and selective epitaxy, controllable C and P alloying with Si, for its qualification as a Si precursor in high volume manufacturing.

Thermodynamic Theory of Silicon Chemical Vapor Deposition

“…In this regime, the growth rate is limited by the desorption of former hydrogen ligands. The trendline is fitted with eq , where GRS is the simulated film growth rate, k is a temperature independent frequency factor in nm/min, E is the activation energy, R is the ideal gas constant, T is the temperature, N is an atomic density, C is the precursor concentration in the gas phase, p SiH 4 0 is the precursor partial pressure, and finally, α is an empirical reaction order . The acronym GRS, standing for Growth Rate Simulated, is used to discriminate theory from experiments.…”

“…The acronym GRS, standing for Growth Rate Simulated, is used to discriminate theory from experiments. There is a large body of experimental results showing α = 1 for silane. , An activation energy of about 193 kJ/mol is commonly reported, but large variations across studies are also noted …”

“…There is a large body of experimental results showing α = 1 for silane. 17,18 An activation energy of about 193 kJ/mol is commonly reported, but large variations across studies are also noted. 16 i k j j j j j j j j y { z z z z z z z z…”

Comparative study of the gas phase reaction of SiCl4, SiHCl3, SiH2Cl2, and SiH3Cl by thermodynamic analysis

“…[1][2][3][4] In addition, there are some reports about CVD using trichlorosilane (SiHCl 3 ) and monochlorosilane (SiH 3 Cl). 5,6) Although the influence of the Cl-introduction to molecular structures has been discussed, there has been a lack of discussion on the difference of the characteristics of the gas-phase reaction between SiH x Cl 4−x (x = 0 ∼ 3) gases. First-principles calculations and kinetics studies for these chlorosilanes have been reported.…”

“…However, it was reported that SiH 2 Cl 2 has a lower silicon growth rate than SiH 3 Cl in the range of 600 °C-850 °C. 6) SiH 3 Cl has a much lower equilibrium partial pressure of HCl, thus, it is expected that silicon growth using SiH 3 Cl gas has a lower effect of etching by HCl and the silicon growth rate is higher than SiH 2 Cl 2 . In cases where the HCl effects need to be reduced in a deposition process, SiH 3 Cl can be a better source gas.…”