Physical and Electrical Analysis of Poly-Si Channel Effect on SONOS Flash Memory.

Jun-Kyo Jeong,Ki-Ryung Nam,Woon-San Ko,Hi-Deok Lee,Ga-Won Lee,Jae-Young Sung

doi:10.3390/mi12111401

Abstract

In this study, polycrystalline silicon (poly-Si) is applied to silicon-oxide-nitride-oxide-silicon (SONOS) flash memory as a channel material and the physical and electrical characteristics are analyzed. The results show that the surface roughness of silicon nitride as charge trapping layer (CTL) is enlarged with the number of interface traps and the data retention properties are deteriorated in the device with underlying poly-Si channel which can be serious problem in gate-last 3D NAND flash memory architecture. To improve the memory performance, high pressure deuterium (D2) annealing is suggested as a low-temperature process and the program window and threshold voltage shift in data retention mode is compared before and after the D2 annealing. The suggested curing is found to be effective in improving the device reliability.

Highlights

IntroductionA polycrystalline silicon (poly-Si) channel is first formed and silicon nitride (Si3 N4 ) as a charge trapping layer (CTL) is deposited
One of the distinct changes in these 3D structures is that a crystalline silicon (c-Si) channel is replaced by a polycrystalline silicon
Micromachines 2021, 12, x FOR PEERgram results show that more traps exist in the polycrystalline silicon (poly-Si) channel device, which is same with the results show that more traps exist in the poly-Si channel device, which is same with the previous physical analysis

Summary

Introduction

A poly-Si channel is first formed and silicon nitride (Si3 N4 ) as a charge trapping layer (CTL) is deposited. In this case, the characteristics of the CTL will be affected with the underlayer’s topology because thickness of the CTL is only a few nm. The memory window, date retention as well as program/erase speed of SONOS devices are most affected by trap properties of CTL [7,8,9]. The physical and electrical properties of SONOS device with poly-Si channel are analyzed. D annealing the reliability of the SONOS device with device with poly-Si channel can be improved at low temperature.

Experiments

Physical Characteristic Analysis

Measurement

Conclusions