Robust shallow trench isolation technique used for 75nm nor flash memory

Influence of ISSG tunnel oxide with decoupled plasma nitridation on erase characteristic of NOR-type floating-gate flash memories

“…In the dry oxide split, tunnel oxide layer was first grown in dry O 2 and then annealed in an N 2 O ambient for bottom nitridation [4]. While in the ISSG oxide split, tunnel oxide film was grown by ISSG process followed by DPN and NO annealing for top and bottom nitridation respectively [3,7].…”

“…In order to minimize the local thinning effect, ISSG (in-situ steam generation) oxidation is proposed [2,3]. It is proved to be a good oxidation method instead of dry oxidation to achieve the thickness uniformity, providing the robust tunnel oxide for the scaled flash memory cells.…”

An advanced tunnel oxide layer process for 65 nm NOR floating-gate flash memories

“…Since high-temperature dry oxidation creates high-quality and good hot-electron reliability of SiO 2 , it has been used in the mainstream processes of advanced flash memory and may survive longer than many expected [5,6]. However, the dry oxidation process has a number of disadvantages, including a large amount of dangling bonds in the SiO 2 /Si interface, local oxide thinning at the shallow-trench isolation (STI) corners, and thickness non-uniformity in the central oxide region [7][8][9]. These disadvantages can result in lower performance and less reliability of the advanced flash cells.…”

“…This low thermal budget, dual oxidation technique could effectively improve the quality of the tunnel oxide layer, but it cannot solve the local thinning effect issue; moreover, it needs dry and wet oxidation processes simultaneously. The additional in-situ steam generation (ISSG) process method was proposed to suppress the local thinning effect at the STI corner by minimizing the orientation dependency of the oxidation rate [9,11]. Unfortunately, applying ISSG oxidation in advanced NOR-type flash technology has little effect on the thickness uniformity in the central oxide region, even though an improvement of local oxide thinning is obtained at the STI corner [9].…”

“…The additional in-situ steam generation (ISSG) process method was proposed to suppress the local thinning effect at the STI corner by minimizing the orientation dependency of the oxidation rate [9,11]. Unfortunately, applying ISSG oxidation in advanced NOR-type flash technology has little effect on the thickness uniformity in the central oxide region, even though an improvement of local oxide thinning is obtained at the STI corner [9]. Besides, Wang et al applied the ISSG process following the sacrificial oxide process for fabricating the gate oxide of the peripheral metal-oxide-semiconductor field-effect transistors (MOSFETs) with 0.13 μm technology [12].…”