Role of the gas temperature and power to gas flow ratio on powder and voids formation in films grown by PECVD technique

R. Martins, V. Silva, I. Ferreira, A. Domingues, E. Fortunato

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

This paper deals with the study of the role of gas temperature and of the ratio of r.f. power to gas flow on the particle's formation in amorphous silicon films grown by plasma enhanced chemical vapour deposition technique, by monitoring the plasma impedance behaviour under different process conditions. The aim is to determine in which conditions the particles formed do not deteriorate the performances of the films grown or even can lead to an improvement of the properties of the films deposited. The results achieved show the existence of two main boundary regions (β- and θ-regions) separating the so-called α-regime (no powder formed) from the γ-regime (powder formed). Those regions are reached either by heating the gas, changing the gas pressure or using high power to gas flow ratios. In the β-region the probability of incorporating nanoparticles in the films is low and the films exhibit properties similar to those of the ones grown in the α-regime, with a low density of voids incorporated. In the θ-region small nanoparticles can be incorporated leading to films with density of states below 5×1015 cm-3, widened Urbach energies and photosensitivities about two orders of magnitude larger than that of conventional amorphous silicon grown in the α-regime.

Original languageEnglish
Pages (from-to)25-30
Number of pages6
JournalVacuum
Volume56
Issue number1
DOIs
Publication statusPublished - Jan 2000

Fingerprint

Dive into the research topics of 'Role of the gas temperature and power to gas flow ratio on powder and voids formation in films grown by PECVD technique'. Together they form a unique fingerprint.

Cite this