Suppression of boron transient enhanced diffusion in SiGe heterojunction bipolar transistors by carbon incorporation

Abstract

In this work, we demonstrate that the incorporation of carbon in the base of a npn Si/SiGe/Si heterojunction bipolar transistor dramatically reduces the outdiffusion of boron from the base under postgrowth implantation and annealing procedures. Without the addition of C, these processes would lead to transistors with vastly degraded transistor characteristics. This reduction in B diffusion, when compared to devices without C, has been observed by both secondary ion mass spectroscopy and improved electrical characteristics.

Base-region optimization of SiGe HBTs for high-frequency microwave power amplification

“…Another option to integrate the base-"optimized" SiGe power HBTs into the existing SiGe BiCMOS platform, which may be considered as a future SiGe BiCMOS, is to separately optimize the base regions of the high-breakdown-voltage SiGe power HBTs (e.g., grow a separate SiGe epilayer with a high doping concentration to achieve a low base resistance). With regard to the suppression of boron outdiffusion in light of the heavy doping level used for the base-region optimization, introducing carbon into the SiGe epilayer has been proven to be effective [21], [22]. To date, this carbon doping technique has been used in many commercial SiGe HBTs [23], [24].…”

Improvement in NiSi/Si contact properties with C-implantation

“…In order to stabilize NiSi, the incorporation processes of the third elements such as Pt, Pd, Ti, N and SiO 2 into Ni/Si system were reported [5][6][7][8][9]. On the other hand, incorporation of C into Si promises several advantages for Si devises, such as energy band engineering [10], controlling impurity diffusion in Si and SiGe substrates [11], and the introduction of the tensile-strain in a Si channel [12]. We have previously reported that the incorporation of a very small amount of C into Si substrate is effective in suppressing the agglomeration of NiSi grains [13].…”

Impact of carbon concentration on the interface density of states of metal-oxide Si1−x−y GexCy (strained) capacitors

“…[1][2][3][4][5] The addition of small amounts of substitutional C in these epilayers is remarkably beneficial as it reduces the out-diffusion of B from the transistor's base. 6 However, the use of Si 1-x Ge x in complementary metal-oxide semiconductor (CMOS) technology has been hindered by the reduced quality of the oxide/epilayer interface. [7][8][9] The benefits of Si 1-x Ge x for CMOS devices rely primarily on increased carrier mobility in comparison to Si and the possibility to master the whole band structure to give superior device performance.…”