The effects of varying plasma parameters on silicon thin film growthby ECR plasma CVD

Abstract

The technique of electron cyclotron resonance (ECR) plasmaenhanced chemical vapour deposition (PECVD) is increasingly being used inelectronic and photonic device applications. ECR offers a number ofadvantages including improved control of the deposition process, lessdamage to the growing film and the possibility of high deposition rates.ECR occurs in a plasma under appropriate magnetic and electric fieldconditions. In most cases, as in our system, this is achieved with acombination of 2.45 GHz microwave radiation and a 0.0875 T magnetic field,due to the use of standardized microwave supplies. We have studied theeffects on silicon film growth of changing the magnetic field configurationto produce one or more planes of ECR within the system, and of changing thepositions of the plane(s) relative to the deposition substrate. The filmswere grown in silane-hydrogen discharges. The magnetic field in our systemwas provided by two electromagnets. It was measured experimentally for anumber of operating current values and then a detailed profile achieved bymodelling using a proprietary software package. A process conditiondischarge under identical magnetic field configurations to growth wasanalysed by the use of a Langmuir probe and the results correlated withfilm properties determined by Raman spectroscopy and Dektak profilometry.