High Performance 400 °C p+/n Ge Junctions Using Cryogenic Boron Implantation

• Published in: IEEE electron device letters Vol. 35; no. 7; pp. 717 - 719
• Main Authors: Bhatt, Piyush, Swarnkar, Prashant, Basheer, Firdous, Hatem, Christopher, Nainani, Aneesh, Lodha, Saurabh
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Applied sciences; Boron; Compound structure devices; contact resistivity; cryogenic implantation; Cryogenics; dopant activation; Electronics; Exact sciences and technology; Germanium; Germanium (Ge); Implants; Junctions; Microelectronic fabrication (materials and surfaces technology); Resistance; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; source/drain junction; Transistors; contact resistivity; dopant activation; source/drain junction; Germanium (Ge); cryogenic implantation; MOS technology; High performance; MOSFET; State of the art; Ion implantation; Electrical conductivity; Surface layer; Carrier to noise ratio; Contact resistance; Cryogenic temperature; Boron; Microelectronic fabrication; Cryogenics; Germanium; p+ n junction
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2014.2326694

We report high performance Ge p + /n junctions using a single, cryogenic (-100 °C) boron ion implantation process. High activation>4 × 10 20 cm -3 results in specific contact resistivity of 1.7 × 10 -8 Ω-cm 2 on p + -Ge, which is close to ITRS 15 nm specification (1 × 10 -8 Ω-cm 2 ) and nearly 4.5× lower than the state of the art (8 × 10 -8 Ω-cm 2 ). Cryogenic implantation is shown to enable solid-phase epitaxial regrowth and lower junction depth through amorphization of the surface Ge layer. These improvements in Ge p + /n junctions can pave the way for future high mobility Ge p-MOSFETs.