Effect of mechanical stress on operation of diode temperature sensors

Abstract

Effect of uniaxial elastic strain (of moderate magnitude) on operation of n+- p-type diode temperature sensor made in silicon is considered theoretically. It is assumed that operating current and stress direction coincide with each other and with one of three main crystallographic directions [100], [110] and [111]. The cases of long and short diodes, compressive and tensile stresses are studied. It is shown that, under such conditions, two components of the piezojunction effect (namely: change in the minority carrier mobility and change in the intrinsic carrier concentration) act oppositely to each other. As a result, effect of longitudinal parasitic mechanical stress on indications of the silicon diode temperature sensors proves to be minimal in the direction of [100]-type [111]-type as it would be expected from rather than piezoresistivity of n-Si.