Ultradoping Boron on Si(100) via Solvothermal Chemistry

• Published in: Chemistry : a European journal Vol. 27; no. 53; pp. 13337 - 13341
• Main Authors: Frederick, Esther, Campbell, Quinn, Kolesnichenko, Igor V., Peña, Luis F., Benavidez, Angelica, Anderson, Evan M., Wheeler, David R., Misra, Shashank
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20.09.2021; ChemPubSoc Europe
• Subjects: Boron; boron-silicon bonds; Catalysts; Chemical bonds; Chemical reactions; Chemistry; Commercialization; Density functional theory; Dopants; Electronic materials; High vacuum; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; monolayers; on-surface reactions; Surface properties; Surface reactions; ultradoping
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202102200

Ultradoping introduces unprecedented dopant levels into Si, which transforms its electronic behavior and enables its use as a next‐generation electronic material. Commercialization of ultradoping is currently limited by gas‐phase ultra‐high vacuum requirements. Solvothermal chemistry is amenable to scale‐up. However, an integral part of ultradoping is a direct chemical bond between dopants and Si, and solvothermal dopant‐Si surface reactions are not well‐developed. This work provides the first quantified demonstration of achieving ultradoping concentrations of boron (∼1e14 cm2) by using a solvothermal process. Surface characterizations indicate the catalyst cross‐reacted, which led to multiple surface products and caused ambiguity in experimental confirmation of direct surface attachment. Density functional theory computations elucidate that the reaction results in direct B−Si surface bonds. This proof‐of‐principle work lays groundwork for emerging solvothermal ultradoping processes. Ultradoping, i. e. using direct dopant‐Si chemical bonds to dope past the Si solid solubility limit, changes the behavior of Si and makes it promising for use in next‐generation devices. While solvothermal methods enable scalability and commercialization, there is little precedence for solvothermal formation of on‐surface B−Si bonds. This work provides the first demonstration of solvothermally achieving ultradoping levels of B (∼1e14 cm2).