THE FRACTURE-TOUGHNESS OF POLYSILICON MICRODEVICES - A FIRST REPORT

Polysilicon microfracture specimens were fabricated using surface micr omachining techniques identical to those used to fabricate microelectr omechanical systems (MEMS) devices. The nominal critical J-integral (t he critical energy release rate) for crack initiation, J(c), was deter mined in specimens whose characteristic dimensions were of the same or der of magnitude as the grain size of the polysilicon. J(c) values ran ged from 16 to 62 N/m, approximately a factor of four larger than J(c) values reported for single crystal silicon.