Curing of oxide damage in a MOSFET with joule heat by forward junction current

Abstract

This research demonstrates a method for curing the gate dielectric of a MOSFET using Joule heat (JH) generated by the forward bias current of the PN-junction in the drain-to-body (D-B) and source-to-body (S-B). The curing method was applied to repair hot-carrier induced damage in the MOSFET. In the first part, the short-channel effects (SCEs) resulting from the increased lateral electric will be discussed. The MOSFET has been continuously scaled to achieve advantages such as increased device speed and packing density. However, the SCEs have become more serious due to aggressive channel length (LG) scaling. In the second part, curing methods for restore the degraded gate dielectric of MOSFET are studied. As a conventional method, forming gas annealing (FGA) has been widely used in the device fabrication processes. As a local annealing method, Joule heat, which is created by applying voltage between dual gate pads, has been used as an alternative. To overcome the weakness in the previous Joule heat method, a novel curing method with Joule heat generated by forward junction current is proposed. In the third part, the curing process using Joule heat is verified by comparing of device parameters and LFN characterization method. After occurring of hot-carrier injection (HCI), the gate dielectric of the device is degraded by the injected hot-carrier. By observing the device parameters and the extracted average trap density, the curing effect is quantitatively verified. In the last section, the difference curing effect of the JH at S-B and D-B junction is accurately quantify by charge pumping characterization method.