Silicon Growth Rate Enhancement Using Trisilane in a Laser Direct-Writing Technique

Abstract

ABSTRACTAn argon-ion laser based direct-writing technique was used to deposit micron-size silicon lines from the decomposition of silane (SiH4) and trisilane (Si3H8) gases. The substrates used were 0.1 μrn polysilicon/1 μ.m silicon dioxide/<100> monosilicon multilayered structures. The vertical silicon deposition rate was investigated as a function of the laser-induced surface temperature and gas pressure. For temperatures ranging between 1000 and 1410 °C, the pressure was varied in the range 5-250 mbar and 0.1-30 mbar for SiH4 and Si3H8, respectively. For both gases, three growth regimes could be distinguished according to precursor pressure. The deposition rates achieved using trisilane are far higher than those obtained with silane in spite of the use of a reduced gas pressure range. For a laser-induced surface temperature of 1300 °C and a precursor pressure of 10 mbar, the deposition rates achieved using SiH4 and Si3H8 are, respectively, 0.42 and 20 μ.m/s, representing an enhancement factor of 50 with the later.