Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Citation - WoS: 5Citation - Scopus: 5Determination of the Dill Parameters of Thick Positive Resist for Use in Modeling Applications(Elsevier Ltd., 2011) Roeder, G.; Liu, S.; Aygün, Gülnur; Evanschitzky, P.; Erdmann, A.; Schellenberger, M.; Pfitzner, LThe determination of Dill parameters of thick resist is very important to improve simulation models of resist exposure and real world processes. A new extraction technique of Dill parameters based on spectroscopic ellipsometry in combination with an advanced resist exposure model is proposed for thick resist analysis. The complex refractive index of the resist is related to the relative concentration of the photoactive compound in the resist in order to describe the vertical distribution of the refractive index and the extinction coefficient. Moreover, Dill parameters are extracted by directly fitting the bleaching curves to the measured ellipsometry data. The new approach was investigated experimentally by spectroscopic ellipsometry measurements on AZ5214E resist with two moderate layer thickness values in order to verify the accuracy of the new method. Dill parameters were extracted by using this new technique and by applying resist samples subjected to different exposure doses. Possible reasons for the variation of Dill parameters depending on resist thickness are explained. Furthermore, advantages, limitations and potential improvements of the model are discussed. Finally, the impact of Dill parameter variation on image formation in the resist is demonstrated by applying the spectroscopic ellipsometer analysis results as input parameters to the lithography simulator Dr.LiTHO.Article Citation - WoS: 15Citation - Scopus: 13Impact of temperature increments on tunneling barrier height and effective electron mass for plasma nitrided thin Sio2 layer on a large wafer area(American Institute of Physics, 2010) Aygün, Gülnur; Roeder, G.; Erlbacher, T.; Wolf, M.; Schellenberger, M.; Pfitzner, L.Thermally grown SiO2 layers were treated by a plasma nitridation process realized in a vertical furnace. The combination of a pulsed-low frequency plasma and a microwave remote plasma with N2/NH 3/He feed gas mixture was used to nitride the thermally grown SiO2 gate dielectrics of MIS structures. Temperature dependency of effective masses and the barrier heights for electrons in pure thermally grown SiO2 as well as plasma nitrided SiO2 in high electric field by means of Fowler-Nordheim regime was determined. It is frequently seen from the literature that either effective electron mass or barrier height (generally effective electron mass) is assumed to be a constant and, as a result, the second parameter is calculated under the chosen assumption. However, in contrast to general attitude of previous studies, this work does not make any such assumptions for the calculation of neither of these two important parameters of an oxide at temperature ranges from 23 to 110 °C for SiO 2, and 23 to 130 °C for nitrided oxide. It is also shown here that both parameters are affected from the temperature changes; respectively, the barrier height decreases while the effective mass increases as a result of elevated temperature in both pure SiO2 and plasma nitrided SiO 2. Therefore, one parameter could be miscalculated if the other parameter, i.e., effective mass of electron, was assumed to be a constant with respect to variable physical conditions like changing temperature. Additionally, the barrier heights were calculated just by taking constant effective masses for both types of oxides to be able to compare our results to common literature values. © 2010 American Institute of Physics.