Review—Mechanical Stress in Chemically Vapor Phase Deposited Boron- and Phosphorus-Contained Silicate Glass Thin Films: A Review

Abstract

This article provides an overview of the published mechanical stress data for boron-and phosphorus-contained silicate glass films deposited by a variety of chemically vapor deposited (CVD) techniques, i.e. atmospheric and sub-atmospheric pressure (APCVD, SACVD), low pressure, plasma-enhanced (LPCVD, PECVD). The emphasis is done on borophosphosilicate glass films (BPSG) dedicated for the use in micro-electro-mechanical system (MEMS) and micro-opto-electro-mechanical system (MOEMS) technologies as a material with significantly higher film thickness as compared with its traditional use in microelectronics technology as a flow-able planarized interlayer dielectric. The article covers stress features of as-deposited and thermally annealed films with the boron and phosphorus concentration range in between about 1-12 wt%. Phosphorus is detected as a main film component responsible for stress type (tensile or compressive) and its particular values. Film deposition techniques strongly affect the film stress at low phosphorus content in the films, providing either tensile (APCVD, SACVD), or compressive (LPCVD, PECVD) stress types. These effects explained with differences in CVD kinetics and hydrogen-contained CVD reaction by-products formation.