Abstract
A new way to detect gate oxide defects has been developed. The method, as the article explains, is based on wet chemical etching and is particularly effective for devices with floating gates. Test samples with exposed poly-Si gates are placed in a KOH:H2O solution and a voltage is applied to the silicon substrate. At a certain voltage, normal gates begin to etch, while those shorted to the substrate through gate oxide defects develop an anodic oxide and thus remain unetched. This method has proven effective in assessing gate oxide integrity without direct observation of the oxide, which requires complicated deprocessing and a lot of time. It also reveals electrical characteristics of gate oxides that are difficult to identify by conventional physical analysis.
