Three topics which are related to technologies for developing of large capacity MRAM over Gbits are reviewed. First, it is stressed that inelastic-electron-tunnel-tunneling spectroscopy(IETS) is a powerfull method to investigate the interface state between magnetic electrodes and insulator. Second, magnetic tunnel junctions with small bias voltage dependence are introduced. Finally, fabrication method of carbon masks for very small magnetic tunnel junctions is demonstrated. These three topics were presented at 47^{th} MMM 2002 conference and each paper will appear in the proceedings.