Efficient DC and AC analysis of I2L devices based on quasi-three-dimensional modeling

An efficient technique for the modeling of I
²
L devices is developed on the basis of quasi-three-dimensional (Q3D) models, where a device is represented by several one-dimensional model units and the network which combines them. This improved method is capable of treating both dc and ac characteristics within a reasonable computation time. The computed and experimental results are compared, and good agreement is obtained. The importance of high injection effects and lateral voltage drops is clarified for the β
up
falloff of multicollector I
²
L devices at high current levels. The difference between downward and upward operation of the vertical transistor is pointed out. The possibility of applying this method to the optimization of device structure is also shown.