Abstract: A method for tailoring properties of high k thin layer perovskite materials, and devices comprising such insulators are herein presented. The method comprise the steps of, first, substantially completing the manufacture of a device, which device contains the high k insulator in a polycrystalline form. The device, such as a capacitor, or an FET, went through the typically high temperature manufacturing process of a fabrication line. In the next step, the device is in situ ion implanted with such a dose and energy to convert a fraction of the polycrystalline material into an amorphous material state, hereby tailoring the properties of the insulator. The fraction of polycrystalline material converted to amorphous material might be 1. This process can be applied to many electronic devices and some optical devices. The process results in novel perovskite thin layer materials and novel devices fabricated with such materials.