Process for forming a ferroelectric film, ferroelectric film, ferroelectric device, and liquid discharge apparatus

A process for forming a ferroelectric film on a substrate by a sputtering technique, the ferroelectric film containing a perovskite type oxide that is represented by Formula (P) shown below,

• wherein a target, which has a composition in accordance with the film composition of the ferroelectric film to be formed, and the substrate are located at a spacing from each other,
• a shield, which surrounds an outer periphery of the target on the substrate side, is located in a non-contact state with respect to the target, the shield being provided with a plurality of shielding layers, which are superposed one upon another at intervals with respect to the direction of the superposition, and
• the ferroelectric film is formed on the substrate by the sputtering technique under conditions of a height of the shield such that a difference Vs−Vf (V) between a plasma potential Vs (V) in plasma at the time of the film formation by the sputtering technique and a floating potential Vf (V) becomes equal to at most 35V, and under conditions such that a temperature of the substrate becomes equal to at least 400° C.:
• (Pb1−x+δMx) (ZryTi1−y)O— (P)
• wherein M represents at least one kind of element selected from the group consisting of Bi and lanthanide elements,
• x represents a number satisfying the condition of 0.05≦x≦0.4, and
• y represents a number satisfying the condition of 0<y≦0.7,
• the standard composition being such that δ=0, and z=3, with the proviso that the value of δ and the value of z may deviate from the standard values of 0 and 3, respectively, within a range such that the perovskite structure is capable of being attained.