摘要 |
Given a set of hot carrier stress data measured at a fixed level of an operating parameter (e.g., V<SUB>DS</SUB>), my invention predicts what the overall hot carrier stress will be when the same operating parameter is dynamically varied in time pursuant to a predetermined function. One embodiment of my invention is a method of operating a semiconductor device (e.g., a LDMOS FET) that is subject to hot carrier injection (HCI) and is characterized by a device parameter (e.g., R<SUB>ON</SUB>; I<SUB>Dq</SUB>) and a dynamically varied operating parameter (e.g., V<SUB>DS</SUB>, V<SUB>GS</SUB>) comprising the steps of: (a) determining a device parameter that is a measure of the performance of the device; (b) determining the desired lifetime of the device based on an acceptable level of degradation of the device parameter; (c) determining the stress history of the device, including whether or not the device has been previously stressed by HCI; (d) determining the function that describes how the operating parameter is dynamically varied during operation of the device; (e) determining the HCI-induced changes in the device parameter when the operating parameter is fixed in time; (f) based on the stress history of step (c), the function of step (d), and the HCI-induced changes of step (e), determining the HCI-induced degradation of the device parameter; and (g) operating the device with the function if the degradation of step (f) is not greater than the acceptable level of step (b).
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