EFFECTS OF NITRIDE DEPOSITION CONDITIONS ON CHARACTERISTICS OF AN MNOS NON-VOLATILE MEMORY TRANSISTOR

An investigation was carried out of the memory characteristics of MNOS transistors with a nitride film deposited either by normal pressure CVD or low pressure CVD under a variety of conditions. As the SiH4/NH3flow ratio increased in normal pressure CVD, writing anderasing could be executed by smaller voltages or shorter pulses, and the memory retention characteristic became worse. An MNOS transistor with a nitride film deposited by low pressure CVD showed somewhat different memory characteristics. The composition of the nitride/oxide double layers was analyzed by Auger depth profiling and by measurement of the electrical conductivities of the nitride films. The relations between these quantities and the transistor’s memory characteristics are discussed. © 1979 IOP Publishing Ltd.