This paper presents a fabrication process that integrates polysilicon surface micromachining and deep reactive ion etching (DRIE) bulk silicon micromachining. The process takes advantage of the design flexibility of polysilicon surface micromachining and the deep silicon structures possible with DRIE. As a demonstration, a torsional actuator driven by a combdrive moving in the out-of-plane dire...

Polysilicon MEMS structures are coated with self-assembled monolayers (SAMs) to reduce stiction and improve wear resistance. This study reports on an octadecyltrichlorosilane (OTS) coated low pressure chemical vapour deposited (LPCVD) polysilicon based MEMS test structure fabricated at Sandia National Laboratories, USA. The surface morphology and OTS layer have been studied by SEM, XPS and AFM....

With the goal of facilitating the development of surface micromachined polysilicon MEMS with postprocessed on-chip circuitry, we have evaluated the impact of a 1200 C 16-h anneal upon chemical-vapor-deposited (CVD) polysilicon under a variety of processing conditions. The results show that undoped polysilicon has a final stress of +10–20 MPa even when the films are vastly different as deposited...

An analytical model describing the dc voltage and current distributed effects in the polysilicon and intrinsic base regions of long stripe BJT’s with double polysilicon technology is presented. It is shown that the bias dependent debiasing effect in the base polysilicon contacts causes an unequal division of base current between two base polysilicon contacts and results in a redistribution of b...

Conventionally polysilicon is used in MOSFETs for gate material. Doping of polysilicon and thus changing the workfunction is carried out to change the threshold voltage. Additionally polysilicon is not favourable as gate material for smaller dimensional devices because of its high thermal budget process and degradation due to the depletion of the doped polysilicon, thus metal gate is preferred ...

The suspended electrothermal polysilicon micro beams generate displacements and forces by thermal buckling effects. In the previous electro-thermal and thermo-elastic models of suspended polysilicon micro beams, the thermo-mechanical properties of polysilicon have been considered constant over a wide rang of temperature (20900°C). In reality, the thermo-mechanical properties of polysilicon depe...

This paper presents a single wafer, all-silicon, high aspect-ratio multi-layer polysilicon micromachining technology that combines deep dry etching of silicon with conventional surface micromachining to realize tens to hundreds of microns thick, high aspect-ratio, electrically isolated polysilicon structures with sub-micron air-gaps. Vertical polysilicon sense electrodes as tall as the main bod...

A new polysilicon bridge-slider structure (Fig. 1), in which one end of the bridge is fixed and the other is connected to a plate sliding in two flanged guideways, is designed and fabricated to study the strain at fracture of LPCVD polysilicon. In the experiments, a mechanical probe is used to push against the plate end, compressing and forcing the bridge to buckle until it breaks. The distance...

Polysilicon thick films have been found to be an irreplaceable option in various sensors and other microelectromechanical system (MEMS)-designs. Polysilicon is also a prospective option for replacing singlecrystal silicon in customized silicon-on-insulator-substrates. Due to the nature of polysilicon, bonding for MEMS-purposes has so far concentrated on anodic bonding, which has drawbacks for i...

2 A process to fabricate functional polysilicon structures above large (43 4 mm ) thin (200 nm), very flat LPCVD silicon rich nitride membranes was developed. Key features of this fabrication process are the use of low-stress LPCVD silicon nitride, sacrificial layer etching, and minimization of membrane stress and deformation after fabrication, which was done by complete removal of the sacrific...