Highly doped GeSn material is interesting for both electronic and optical applications. GeSn:B is a candidate for source-drain material in future Ge pMOS device because Sn adds compressive strain with respect to pure Ge, and therefore can boost the Ge channel performances. A high B concentration is required to obtain low contact resistivity between the source-drain material and the metal contact. To achieve high performance, it is therefore highly desirable to maximize both the Sn content and the B concentration. However, it has been shown than CVD-grown GeSn: B shows a trade-off between the Sn incorporation and the B concentration (increasing B doping reduces Sn incorporation). Furthermore, the highest B concentration of CVD-grown GeSn: B process reported in the literature has been limited to below 1 x 10(20) cm(-3). Here, we demonstrate a CVD process where B d-doping layers are inserted in the GeSn layer. We studied the influence of the thickness between each d-doping layers and the d-doping layers process conditions on the crystalline quality and the doping density of the GeSn: B layers. For the same Sn content, the d-doping process results in a 4-times higher B doping than the co-flow process. In addition, a B doping concentration of 2 x 10(21) cm(-3) with an active concentration of 5 x 10(20) cm(-3) is achieved. (C) 2017 Elsevier B.V. All rights reserved.