Micromechanical and tribological characterization of doped single-crystal silicon and polysilicon films for microelectromechanical systems devices

Abstract

Microelectromechanical systems (MEMS) devices are made of doped single-crystal silicon, LPCVD polysilicon films, and other ceramic films. Very little is understood about tribology and mechanical characterization of these materials on micro-to nanoscales. Micromechanical and tribological characterization of p-type (lightly boron-doped) single-crystal silicon (referred to as "undoped"), p 1 -type ( boron doped) single-crystal silicon, polysilicon bulk, and n 1 -type (phosphorous doped) LPCVD polysilicon films have been carried out. Hardness, elastic modulus, and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Friction and wear properties were measured using an accelerated ball-on-flat tribometer. It is found that the undoped silicon and polysilicon bulk as well as n 1 -type polysilicon film exhibit higher hardness and elastic modulus than the p 1 -type silicon. The polysilicon bulk and n 1 -type polysilicon film exhibit the lowest friction and highest resistance to scratch and wear followed by the undoped silicon and with the poorest behavior of the p 1 -type silicon. During scratching, the p 1 -type silicon deforms like a ductile metal. 54

Analysis of onset of dislocation nucleation during nanoindentation and nanoscratching of InP

“…Although, the friction coefficient between diamond and InP remains unknown, 39 this result is in good agreement with the commonly observed value of 0.1 for the friction of diamond on semiconductor surfaces. 40 An AFM topographical investigation was carried out on a scratch at a load of 0.4 mN to assess the deformation at the nanometer scale and the results are presented in Fig. 5.…”

Spatial evolution of friction of a textured wafer surface

“…Figure 1 shows a photo of the Ni-Si wafer prior to testing. The hardness of Si is 13 GPa [16], SiO 2 is 9 GPa [17], and Ni is 600 MPa [18]. The sample was rinsed with acetone for 20 minutes in an ultrasonic cleaner prior to the friction test.…”

Nanoindentation Behaviour and Microstructural Evolution of Au/Cr/Si Thin Films

“…0.64 GPa, 16) but less than that of the Si (100) substrate (13 GPa) 14) due to the presence of the Au layer. Li et al 18,19) examined the hardness of undoped silicon, p þ -type silicon, polysilicon bulk and n þ -type polysilicon film using a nanoindentation technique at loads varying from 0.2 to 15 mN. Their results showed that the polysilicon bulk specimen exhibited the highest hardness of around 13 GPa, followed by the undoped Si(100), the n þ -type polysilicon film, and finally the n þ -type silicon, with a hardness of around 5 GPa.…”