The realization of SCH multilayer structure with ultra-thin GaAs active layer using a modified graphite boat system and low temperature technology is demonstrated.Our method utilizes thin solutions and saturation wafers to achive GaAs epituxial layer in the thickness of 25～35 nm which is uniform over relatively large area. Broad-contact LDs using the above mentioned epitaxial wafers are fabricated. These devices have threshold current density of 700～800 A/cm2 at room temperature.