We propose a quantum dot (QD) laser with the half-etched mesa distributed feedback (HEM DFB) structure fabricated by single-step dry etching. The HEM DFB structure provides several advantages, such as low scattering loss and wavelength stability. In this study, we demonstrated a low threshold current of 23 mA and a high thermal stability of 0.077 nm/K for 1.3 µm ground state emission. We also improved the performance of the slope efficiency of HEM DFB lasers by using Cl2 dry etching.