Title: Nanoscale Junction Formation by Gas-Phase Monolayer Doping

Abstract

A major challenge in transistor technology scaling is the formation of controlled ultrashallow junctions with nanometer-scale thickness and high spatial uniformity. Monolayer doping (MLD) is an efficient method to form such nanoscale junctions, where the self-limiting nature of semiconductor surfaces is utilized to form adsorbed monolayers of dopant-containing molecules followed by rapid thermal annealing (RTA) to diffuse the dopants to a desired depth. Unlike ion implantation, the process does not induce crystal damage, thus making it highly attractive for nanoscale transistor processing. To date, reported MLD processes have relied on solution processing for monolayer formation. Gas-phase processing, however, benefits from higher intra- and interwafer uniformity and conformal coverage of 3D structures and is more desirable for manufacturing. In this regard, we report a new approach for MLD in silicon and germanium using gas-phase monolayer formation. We call this technology gas-phase monolayer doping (GP-MLD). This method relies on sequential pulse-purge cycles of gas-phase dopant-containing molecules to form a boron- or phosphorus-containing monolayer on a target semiconductor surface. Here, we show the feasibility of our approach through the formation of ultrashallow B- and P-doped junctions on Si and Ge surfaces. The mechanism of adsorption is characterized using Fourier transform infrared spectroscopy andmore » X-ray photoelectron spectroscopy. Sub-5 nm junction depths with high dopant dose are obtained as characterized by secondary ion mass spectrometry and sheet resistance measurements. Additionally, we demonstrate that area selectivity can be achieved via lithographic patterning of the monolayer dopants before the diffusion step. The results demonstrate the versatility of the GP-MLD approach for formation of controlled and ultrashallow junctions.« less

Authors:

Taheri, Peyman ^[1]; Fahad, Hossain M. ^[2]; Tosun, Mahmut ^[2]; Hettick, Mark ^[2]; Kiriya, Daisuke ^[2]; Chen, Kevin  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-6726-6132"

Javey, Ali  ^[2]

• Search DOE PAGES for author "Javey, Ali"
• Search DOE PAGES for ORCID "0000-0001-7214-7931"

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States). Electrical Engineering and Computer Sciences; Univ. of California, Berkeley, CA (United States). Berkeley Sensor and Actuator Center
2. Univ. of California, Berkeley, CA (United States). Electrical Engineering and Computer Sciences; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Berkeley Sensor and Actuator Center

Publication Date:

Wed Jun 07 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); The Netherlands Organization for Scientific Research

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1567084

Grant/Contract Number:  

AC02-05CH11231; SC0004993

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 9; Journal Issue: 24; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 42 ENGINEERING