Conformal doping in 3D si structure using conformal dopant deposition

Abstract

Embodiments described herein generally relate to doping of three dimensional (3D) structures on a substrate. In one embodiment, a conformal dopant containing film may be deposited over the 3D structures. Suitable dopants that may be incorporated in the film may include boron, phosphorous, and other suitable dopants. The film may be subsequently annealed to diffuse the dopants into the 3D structures.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit to U.S. Provisional Patent Application No. 62 / 242,146, filed Oct. 15, 2015, the entirety of which is herein incorporated by reference.BACKGROUND[0002]Field[0003]Embodiments described herein generally relate to doping of three dimensional (3D) structures formed on a substrate. More specifically, embodiments described herein relate to conformal doping in 3D silicon structures using conformal dopant deposition processes.[0004]Description of the Related Art[0005]Three dimensional (3D) transistors, such as fin field-effect transistors (FinFETs) are promising candidates to extend complimentary metal-oxide semiconductor (CMOS) scaling. Such FinFET transistors generally provide for improved electrostatic control (i.e. short channel effects) and lower sensitivity to random dopant fluctuations. However, implementation challenges and process complexity issues exist in the integration of FinFETs at advanced technology ...

AI Technical Summary

Benefits of technology

The patent text describes a method for doping three-dimensional structures formed on a substrate, such as FinFET devices. The method involves depositing a conformal film on the structures, which can contain both a dopant and a non-dopant material like carbon or nitrogen. The film is then annealed to diffuse the dopant into the structures. This method can allow for precise doping of the three-dimensional structures, which can enhance their performance and reliability.

Problems solved by technology

However, implementation challenges and process complexity issues exist in the integration of FinFETs at advanced technology dimensions.

For example, one challenge of FinFET integration is dopant concentration in 3D silicon containing device structures.

As a result of the lack of a body or back gate bias in fully depleted (i.e. no mobile carriers) FinFET device structures, complicated workfunction engineering is often necessary to achieve workable threshold voltages for undoped FinFETs.

In addition to threshold voltage complications, dopant concentration and dopant distribution within the FinFET structures present additional challenges in 3D device structure manufacturing processes.

In angled ion implantation schemes, dopant concentration and distribution specificity is difficult to control and such systems are expensive to implement in processing sequences.

Additionally, throughput may be negatively affected with additional apparatus used to perform doping operations.

Line of sight schemes may be used to deposit dopant films on FinFETs, but the 3D structure of FinFETs prevent suitable film deposition characteristics (i.e. deposition on sidewalls of 3D structures) which adversely affects dopant distribution and concentration within the FinFET structures.

Images