The study presents the results of an experimental investigation of the role of sophisticated monolithic linear X ray strip detectors based on semi-insulating (SI) GaAs introducing etched trenches around strips into the technology. The strip line detectors are preferably determined for application in digital X-ray imaging. Investigated strip detectors were created by evaporation of Au/Zn (top) and AuGeNi (bottom) eutectic alloys, respectively onto LEG SI GaAs wafer using lift-off technique. Topology of strip line was modified by trenches using RIE etching around the detector strip. The influence of the trenches on detection properties of strip detectors are investigated in terms of charge collection efficiency, energy resolution and detection efficiency using gamma sources 241 Am and 57 Co. Obtained results show worsening of CCE in the case of trench placed on the bottom - ohmic side of detector, otherwise an improvement of energy resolution after etching treatment was observed. Current-voltage measurements show remarkable decrease of reverse current after etching the trenches.