An implantable electrode array (30) that can adopt a first configuration selected to allow the array (30) to be inserted into a cochlea (12) of an implantee and at least a second configuration in which the array can apply tissue stimulation. The array (30) comprises an elongate carrier (31) having a proximal end (37), a distal end (34), and an inner surface (35) conformable with the inner wall of the implantee's cochlea (12). A plurality of electrodes (36) are supported within the carrier (31) at respective spaced locations thereon in a region between the proximal end (37) and the distal end (34) with at least one of the electrodes having a surface that is at least adjacent the inner surface (35) of the carrier (31). The carrier (31) is formed in the second configuration from a first layer (32) and at least a second layer (32) of resiliently flexible material. A method of forming an array (30) is also described.