Thermal stability for Te-based devices

• Published in: Applied physics letters 2020-11, Vol.117 (19)
• Main Authors: Zhao, Chunsong, Hurtado, Luis, Javey, Ali
• Format: Article
• Language: English
• Subjects: Annealing; Applied physics; Encapsulation; Failure mechanisms; Graphene; Optoelectronic devices; Performance degradation; Semiconductor devices; Sublimation; Tellurium; Thermal instability; Thermal stability; Transistors
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0018045

Tellurium (Te) has recently been rediscovered as an attractive semiconducting material for a wide range of electronic and optoelectronic applications. However, thermal instability of Te-based devices has not been investigated and introduces major drawbacks for their practical applications. Toward this goal, this work explores the influence of annealing temperatures on Te transistors and their two failure mechanisms, related to the sublimation of the Te channel and the degradation of the contacts. To overcome these challenges, we fabricated a Te device that is graphene-contacted and SiOx-encapsulated such that the Te channel and the contacts remain intact and stable at high temperatures. The device exhibits an effective mobility of ∼50 cm2 V−1 s−1, which is comparable to traditional metal-contacted Te transistors. The traditional Te devices have performance degradation with increasing temperature and failure at 200 °C. Through the graphene contact and SiOx encapsulation, our device shows improved thermal stability despite the repeated annealing processes for temperatures up to 250 °C, making it suitable for practical use.