Monolayer molybdenum disulfide (MoS₂) has emerged as one of the most promising channel materials for next-generation nanoelectronics and optoelectronics owing to its atomic thickness, dangling-bond-free flat surface, and high electrical quality. Currently, high-quality monolayer MoS₂ wafers are primarily grown on sapphire substrates incompatible with conventional device fabrication, and thus transfer processes to a suitable substrate are typically required before the device can be processed. Here, we demonstrate the batch production of transfer-free MoS₂ top-gate devices directly on sapphire growth substrates via step engineering. By introducing substrate steps on growth substrate sapphire, high-κ dielectric layers with superior quality and uniform can be directly deposited on the epitaxially grown monolayer MoS₂. For the substrate with a maximum step density of 100 μm⁻¹, the gate capacitance can reach ~ 1.87 μF∙cm⁻², while the interface trap state density (D_it) can be as low as ~ 7.6 × 10¹⁰ cm⁻²∙eV⁻¹. The direct deposition of high-quality dielectric layers on grown monolayer MoS₂ enables the batch fabrication of top-gate devices devoid of transfer and thus excellent device yield of > 96%, holding great promise for large-scale two-dimensional (2D) integrated circuits.