Characterization of carrier generation in enhancement-mode SOI MOSFET's

The carrier generation in enhancement-mode SOI MOSFETs is studied by applying a suitable bias step on one gate, which drives it from depletion of accumulation to stronger accumulation and creates a deep-depletion condition under the other gate. An accurate analysis of this technique is made through a critical reexamination of the physical mechanisms and assumptions involved. By carefully considering all the essential events taking place in the device as it relaxes back to steady state, a Zerbst-type expression is obtained for the resulting current transients, which leads to a straightforward evaluation of the generation lifetime and surface generation velocity. The method is used to study SIMOX transistors, and it is shown that a very long lifetime can be achieved by multiple oxygen implants.>