On the electrical properties of the I2L n-p-n transistor

The optimization of the I
²
L speed-power product requires a clear understanding of the physical mechanisms that control device performance. Test structures have been designed and fabricated to characterize both intrinsic and extrinsic elements of an I
²
L gate. The electrical properties of the intrinsic n-p-n transistor are compared to calculations. Good agreement between measured and calculated beta is obtained for both the up and down transistor without parametric fitting. Band shrinkage, degeneracy, and Auger recombination are found to be important factors in determining the n-p-n base current. Intrinsic up betas greater than 2000 have been measured. The importance of n-p-n beta on the unit cell effective beta and the gate switching time is discussed.