Owing to their high sensitivity, high signal-to-noise ratio, and fast response speed, InGaAs/Si avalanche photodiodes (APDs) are utilized in various applications, including low light signal detection, long-distance fiber optic communication, laser ranging, and laser guidance. However, the high penetration dislocation density at the InGaAs/Si heterojunction interface, caused by the 7.7% lattice mismatch and maximum conduction band order between InGaAs and Si, results in large dark currents and complicates avalanche breakdown within APDs. To achieve high performance in InGaAs/Si APDs, this study introduces an eight-layer InGaAs gradient buffer at the InGaAs/Si bonding interface to reduce the charge carrier accumulation at the heterojunction interface. We have also innovatively added air grooves to the Si multiplication layer to replace the charge layer and modify the electric field. We investigat the influence of groove depth on the performance of the charge-free InGaAs/Si APDs at the bonding interface. Our research found that the current, recombination rate, impact ionization rate, electric field, and gain-bandwidth product of the InGaAs/Si APDs are optimized at groove depths of 150 and 300 nm. These findings provide theoretical guidance for the subsequent development of InGaAs/Si APDs with simplified processes, stable performance, and low noise.