Seed layer processes for MOCVD of ferroelectric thin films on high-k gate oxides

A method of forming a ferroelectric thin film on a high-k layer, comprising:

• preparing a silicon substrate;
• forming a high-k layer on the substrate of material taken from the group of materials consisting of HfO2 and (Zr0.5,Hf0.5)O2, to a thickness of between about 3.5 nm to 15 nm;
• depositing a seed layer of PGO ferroelectric material at a relatively high temperature on the high-k layer;
• depositing a top layer of ferroelectric material on the seed layer at a relatively low temperature;
• and
• annealing the substrate, the high-k layer and the ferroelectric layers to form a ferroelectric thin film.

A method of forming a ferroelectric thin film on a high-k layer, comprising:

• preparing a silicon substrate;
• forming a high-k layer on the substrate of material taken from the group of material consisting of HfO2 and (Zr0.5,Hf0.5)O2, to a thickness of between about 3.5 nm to 15 nm;
• depositing a seed layer of ferroelectric material at a relatively high temperature on the high-k layer, including depositing a layer of c-axis oriented PGO thin film at a temperatures of between about 500° C. to 540° C., at a pressure of between about 1 torr to 5 torr, in an atmosphere having an oxygen partial pressures of between about 20% to 30%, at a vaporizer temperature of between about 180° C. to 200° C.;
• wherein a precursor solution has a delivery rate of between about 0.05 ml/min to 0.1 ml/min, for a deposition time of between about 5 minutes to 20 minutes;
• depositing a top layer of ferroelectric material on the seed layer including depositing a PGO thin film at a deposition temperatures of between about 380° C. and 420° C., wherein the deposition pressure is between about 5 torr to 10 torr, in an atmosphere having an oxygen partial pressure of between about 30% to 40%, at a vaporizer temperature of between about 200° C. to 240° C., wherein a precursor solution delivery rate is between about 0.1 ml/min to 0.2 ml/min;
• and wherein the deposition time is between about one hour to three hours;
• and
• annealing the substrate, the high-k layer and the ferroelectric layers at a temperature of between about 520° C. to 560° C. for between about thirty minutes and one hour in a pure oxygen atmosphere to form a ferroelectric thin film.