  The hybrid photon-atom integrated circuits, which include photonic
microcavities and trapped single neutral atom in their evanescent field, are of
great potential for quantum information processing. In this platform, the atoms
provide the single-photon nonlinearity and long-lived memory, which are
complementary to the excellent passive photonics devices in conventional
quantum photonic circuits. In this work, we propose a stable platform for
realizing the hybrid photon-atom circuits based on an unsuspended photonic
chip. By introducing high-order modes in the microring, a feasible
evanescent-field trap potential well $\sim0.3\,\mathrm{mK}$ could be obtained
by only $10\,\mathrm{mW}$-level power in the cavity, compared with
$100\,\mathrm{mW}$-level power required in the scheme based on fundamental
modes. Based on our scheme, stable single atom trapping with relatively low
laser power is feasible for future studies on high-fidelity quantum gates,
single-photon sources, as well as many-body quantum physics based on a
controllable atom array in a microcavity.
