An integrated circuit, IC, structure including: a substrate; a transistor device on the substrate, the transistor device comprising: a channel structure including a semiconductor material; a gate stack including a metal, the gate stack on the channel structure; a source structure in a first trench at a first side of the gate stack; a drain structure in a second trench at a second side of the gate stack; individual ones of the source structure and the drain structure including a source or drain, source/drain, liner comprising a doped epitaxial layer conformal with a surface of a corresponding one of the first trench and the second trench; and a fill structure filling a portion of a corresponding one the first trench and the second trench, the fill structure adjacent to and compositionally different from the source/drain liner; and metal contact structures coupled to respective ones of the source structure and the drain structure, wherein the doped epitaxial layer is a first doped epitaxial layer, the source/drain liner including a second doped epitaxial layer disposed on, conformal with and compositionally different from the first doped epitaxial layer, and characterized in that the first doped epitaxial layer includes boron doped silicon germanium and has an atomic percentage of germanium that is 50% or more, and the second doped epitaxial layer includes boron doped germanium and has an atomic percentage of silicon that is from 0% to 5%, wherein a doping concentration of boron in the second doped epitaxial layer is more than a doping concentration of boron in the first doped epitaxial layer. a substrate; a transistor device on the substrate, the transistor device comprising: a channel structure including a semiconductor material; a gate stack including a metal, the gate stack on the channel structure; a source structure in a first trench at a first side of the gate stack; a drain structure in a second trench at a second side of the gate stack; individual ones of the source structure and the drain structure including a source or drain, source/drain, liner comprising a doped epitaxial layer conformal with a surface of a corresponding one of the first trench and the second trench; and a fill structure filling a portion of a corresponding one the first trench and the second trench, the fill structure adjacent to and compositionally different from the source/drain liner; and metal contact structures coupled to respective ones of the source structure and the drain structure, wherein the doped epitaxial layer is a first doped epitaxial layer, the source/drain liner including a second doped epitaxial layer disposed on, conformal with and compositionally different from the first doped epitaxial layer, and characterized in that the first doped epitaxial layer includes boron doped silicon germanium and has an atomic percentage of germanium that is 50% or more, and the second doped epitaxial layer includes boron doped germanium and has an atomic percentage of silicon that is from 0% to 5%, wherein a doping concentration of boron in the second doped epitaxial layer is more than a doping concentration of boron in the first doped epitaxial layer. a channel structure including a semiconductor material; a gate stack including a metal, the gate stack on the channel structure; a source structure in a first trench at a first side of the gate stack; a drain structure in a second trench at a second side of the gate stack; individual ones of the source structure and the drain structure including a source or drain, source/drain, liner comprising a doped epitaxial layer conformal with a surface of a corresponding one of the first trench and the second trench; and a fill structure filling a portion of a corresponding one the first trench and the second trench, the fill structure adjacent to and compositionally different from the source/drain liner; and metal contact structures coupled to respective ones of the source structure and the drain structure, wherein the doped epitaxial layer is a first doped epitaxial layer, the source/drain liner including a second doped epitaxial layer disposed on, conformal with and compositionally different from the first doped epitaxial layer, and characterized in that the first doped epitaxial layer includes boron doped silicon germanium and has an atomic percentage of germanium that is 50% or more, and the second doped epitaxial layer includes boron doped germanium and has an atomic percentage of silicon that is from 0% to 5%, wherein a doping concentration of boron in the second doped epitaxial layer is more than a doping concentration of boron in the first doped epitaxial layer.