The concept of atomically controlled CVD technology for group IV semiconductors is based on atomic-order surface reaction control. The epitaxial growth of strained Si1-x-yGexCy layer with high Ge fraction and high C fraction on unstrained and tensile-strained Si(100) is performed at 500 or 550°C by ultraclean low-pressure CVD. The relationship between vertical lattice constant and Raman shift in strained Si 1-x-yGexCy layer with high Ge and high C fraction is explained quantitatively. It is confirmed that growth characteristics as well as electrical activity of impurity in the strained layer are influenced by the substrate surface strain. The influence of atomic-layer doping on strain in epitaxial growth are described. These results open the way to atomically controlled CVD technology for doping and strain engineering for future device generations.