A Study Of Sb Based And Doped Phase Change Material

The present era is an era of information explosion, with the rapidgrowth of information, the requirement of memory device as an informationcarrier is increasing. Currently the most widely used non-volatile memory isflash memory. However, because of the limit of flash storage mechanism, inthe foreseeable future flash memory can’t meet the requirements of portablestorage. The PRAM （Phase Change Random Access Memory） technology, anew generation of non-volatile memory technology,based on chalcogenide,characterised by non-volatile, long cycle life, low power consumption, fastread/write speed, anti-radiation and compatibility with CMOS technology,is considered most likely to replace the current flash memory and a possiblefuture universal memory technology. The phase change materialGe-Sb-Te（GST） film is most widely used in PRAM device. With thedeepening of the study, GST film as the storage medium of PRAM alsoexposed some inherent insufficient to meet the requirements of futurenon-volatile memory technology, for example high RESET current. Todecrease RESET current of PRAM，we did some research on the following:1. Calculation, and plot the distribution of phase change materials. It indicates the value of elements compounds iconicity-hybridization has acertain correlation with the crystallization temperature, crystal structure. Itshows some guidance of the choosing of future phase change materials.2. SiNx-doped Sb₂Te₃films were deposited co-sputtering with Si3N4and Sb₂Te₃targets. XRD patterns show the main crystallization phase ofSiNx-doped Sb₂Te₃film is Sb₂Te₃. In the Sb content increases, there will beSb7Te phase, which will significantly reduce the amorphous resistivity.Sb₂Te₃film doped with SiNximproved crystalline and amorphous resistivity,the resistance change rate is greater than106. Compared with the GST film,SiNxdoped Sb₂Te₃film with higher crystalline resistivity is conducive toreducing devices RESET current.3. A memory device based on SiNx-doped Sb₂Te₃film was fabricated.The device has a memory switching characteristics. The device can haveSET operation at the pulse2.2V-80ns-50ns （Pulse Amplitude-Width-Failingedge）and RESET operation at the pulse4V-20ns-5ns. Device size hassignificant impact on the transition. The size of the device is smaller, therequirement of SET/RESET pulse energy is smaller.