The influence of scaling effects on the characteristics of mesapiezoresistors with dielectric insulation

The influence of the width of polysilicon mesapiezoresistors with dielectric insulation and silicon dioxide passivation on their sheet resistance and piezosensitivity is investigated experimentally. A strong increase in the sheet resistance upon decreasing the width of mesapiezoresistors is found in the range 3 μm ≤ W ≤ 10 μm, which is associated with a decrease in the cross section and impurity segregation in the course of oxidation. It is established that a decrease in the width leads to an increase in the longitudinal piezosensitivity and a drop of the transverse piezosensitivity. The temperature coefficient of resistance (TCR) for the narrower boron-doped resistors weakly decreases for the selected concentration and remains constant for phosphorus-doped resistors. Form factor simple model is suggested to interpret the behavior of the submicron piezoresistors TCR. It is experimentally found that the TCR of polysilicon p-type mesapiezoresistors with submicron resistors array decreases while the resistor strips cross-section sizes decrease.