GaAs-based Erasable Programmable Read Only Memory

We propose to develop and implement a prototype GaAs-based electrically erasable programmable read only memory (EEPROM0 by exploiting wet oxidation of AlAs, which we have already used to successfully integrate GaAs MESFETs and VCSELs. Though EPROMs are readily fabricated using conventional silicon-based fabrication technology, they do not exist in compound semiconductor technology such as GaAs ICs.An EPROM consists of a floating gate, a control gate, a source, and drain electrodes on top of a semiconductor channel. In the device, charges are injected from the silicon across the insulator. The stored charge in the floating gate gives rise to a threshold voltage shift, and the shift is detected in the drain-source voltage for reading. The main reason why EPROMs ( or in general, nonvolatile memories) are not possible in the GaAs technology is because of a relatively large gate leakage current.Our recent work, and the work of others shows that the Al-oxide (A12O3{4}) formed in a thermal process possesses several favorable properties that can also be utilized to reduce leakage currents in GaAs structures. Based on the interesting results we have generated todate, we believe that there is a good chance to demonstrate an EPROM using A1-oxide layers. We will fully characterize the leakage, interface state density, reliability, etc. of the layer suitable for EPROM applications. We will also design, simulate, fabricate, and fully test an EPROM prototype device incorporating Al-oxides.