InGaAs 8×1 linear arrays photodetectors with n-on-p structure and deep mesa, which can response at extended wavelength of 2.4 μm, were fabricated by ICP etching (inductively coupled plasma etching) process in the paper. The device surface was cleaned by N2 plasma activated by ICP, then SiNx passivation layer was deposited by ICPCVD (inductively coupled plasma chemical vapor deposition)) on the device surface. The current-voltage analysis of different area devices indicated that the lateral surface current was suppressed effectively at both room and lower temperature. Activation energy analysis illustrated the excellent dark current characteristics. At -10 mV bias, the dark current density is 94.2 nA/cm2 and 5.5×10-4 A/cm2 at temperatures of 200 K and 300 K, respectively.