Effect of stress in passivation films on shift in the threshold voltage of GaAs transistors is analyzed using a finite element method. Stress field devoloped in the transistor structure is analyzed by considering thermal stress and intrinsic stress of thin films. Localized polarization and the stress-induced-charge density devoloped in the transistor structure are calculated by considering both the piezoelectric effect of GaAs and the predicted stress field in the transistor structure. It is possible to quantitatively predict the shift in the threshold voltage of the transistor, which is mainly caused by the passivation-film stress, by integrating the calculated density of the stress-induced charge in the transistor area. The minimum shift of about 0.1 V is obtaine d when the film stress is -50 MPa. The predicted shift in the threshold voltage agrees well with the measured result.
|Number of pages||6|
|Journal||Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - 2000|
- Piezoelectric effect
- Residual stress
- Stress concentration
- Structural analysis