In this work, we investigate the ohmic contact and thermal stability of silver (Ag) reflective electrode on the p-GaN layer of 1024 pixelated micro light-emitting diode (μ-LED) arrays by two different types of Ag deposition methods. The Ag reflective electrode was deposited on the ITO treatment (which creates ITO nanoparticles) p-GaN layer by radio-frequency magnetron sputter and electronꠓbeam (E-beam) evaporator methods. The electrical properties of the Ag electrodes are evaluated by transmission line method. Sputtered Ag electrodes shows low contact resistance with better ohmic contact properties than the E-beam evaporated Ag electrode. Both films show high reflectance over 91% at 450 nm. These films are then applied on the 1024 pixelated μ-LED arrays as a reflective electrode. After fabrication of μ-LED arrays, the device with E-beam evaporated Ag shows the adhesion issue. On the other hand, the sputtered Ag reflective electrode-based devices show a lower forward voltage 3.26 V at 11 mA than the E-beam evaporated Ag based devices (4.21 V). Sputtered Ag based μ-LED arrays have higher light output power (LOP) compared to the E-beam evaporated μ-LED arrays. Even after thermal aging at 250 oC, the sputtered Ag based μ-LED arrays have higher LOP. In addition, the sputtered Ag based μ-LEDs have high thermal stability than the Eꠓbeam evaporated Ag based μ-LEDs. Furthermore, sputtered AgCu reflective electrode based µ-LED arrays shows smaller forward voltages, higher LOP, and uniform light intensity distribution than the sputtered Ag based µ-LEDs after thermal treatment. These results represent that the sputtered AgCu based μ-LED arrays have better thermal stability compared to the Ag based devices for fabricating high performance μ-LED arrays.