Bias-polarity-dependent resistance switching in W/SiO2/Pt and W/SiO2/Si/Pt structures.

Area of Science:

• Materials Science
• Electrical Engineering
• Solid State Physics

Background:

• Silicon dioxide (SiO2) is a crucial insulator in semiconductor devices.
• Defective SiO2 layers are increasingly utilized as active resistance switching (RS) layers in memory devices.
• Understanding RS mechanisms is vital for next-generation memory technologies.

Purpose of the Study:

• To investigate the impact of electroforming bias polarity on RS behaviors in W/SiO2/Pt structures.
• To elucidate the distinct switching mechanisms (electronic vs. ionic) induced by different bias polarities.
• To assess the influence of film morphology and an intervening Si layer on RS performance.

Main Methods:

• Fabrication of W/SiO2/Pt memory cells.
• Current-voltage (I-V) sweep measurements to analyze resistance switching.
• Electroforming with varying bias polarities (negative and positive).
• Light illumination studies to confirm switching mechanisms.
• Fabrication and testing of devices with an intervening Si layer.

Main Results:

• Negative bias electroforming resulted in electronic switching with a high resistance ratio (~100) and reliability.
• Positive bias electroforming led to ionic-defect-mediated (conducting filament) RS with lower reliability.
• Distinct RS mechanisms were confirmed by light illumination studies.
• RS performance remained consistent even with improved SiO2 film morphology using an intervening Si layer, indicating inherent material properties.

Conclusions:

• The electroforming bias polarity dictates the dominant resistance switching mechanism in SiO2-based memory cells.
• Electronic switching is favored by negative bias, offering higher reliability.
• Ionic switching mechanisms are observed with positive bias, exhibiting lower reliability.
• The observed RS behaviors are intrinsic to the SiO2 material, irrespective of minor morphological improvements.