New low-stress PECVD poly-SiGe layers for MEMS

C.R. Rusu, Sherif Sedky, Brigette Parmentier, Agnes Verbist, Olivier Richard, Bert Brijs, Luc Geenen, Ann Witvrouw, Franz Lärmer, Frank Fischer, Silvia Kronmüller, V. Leca, A.M. Otter

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)

Abstract

Thick poly-SiGe layers, deposited by plasma-enhanced chemical vapor deposition (PECVD), are very promising structural layers for use in microaccelerometers, microgyroscopes or for thin-film encapsulation, especially for applications where the thermal budget is limited. In this work it is shown for the first time that these layers are an attractive alternative to low-pressure CVD (LPCVD) poly-Si or poly-SiGe because of their high growth rate (100-200 nm/min) and low deposition temperature (520/spl deg/C-590/spl deg/C). The combination of both of these features is impossible to achieve with either LPCVD SiGe (2-30 nm/min growth rate) or LPCVD poly-Si (annealing temperature higher than 900/spl deg/C to achieve structural layer having low tensile stress). Additional advantages are that no nucleation layer is needed (deposition directly on SiO/sub 2/ is possible) and that the as-deposited layers are polycrystalline. No stress or dopant activation anneal of the structural layer is needed since in situ phosphorus doping gives an as-deposited tensile stress down to 20 MPa, and a resistivity of 10 m/spl Omega/-cm to 30 m/spl Omega/-cm. With in situ boron doping, resistivities down to 0.6 m/spl Omega/-cm are possible. The use of these films as an encapsulation layer above an accelerometer is shown.
Original languageEnglish
Pages (from-to)816-825
Number of pages10
JournalJournal of microelectromechanical systems
Volume12
Issue number6
DOIs
Publication statusPublished - 2003

Keywords

  • METIS-217565
  • IR-104476

Fingerprint Dive into the research topics of 'New low-stress PECVD poly-SiGe layers for MEMS'. Together they form a unique fingerprint.

Cite this