Abstract
Metallic thin films are widely used in microelectronics devices such as inter-connections of electric circuit and electrodes of the devices. As a novel process of spatial selective deposition of the metal thin film, self-aligned deposition of copper thin films with combination of krypton fluoride excimer laser doping and succeeding electroplating has been demonstrated. The N-plus layer of N type gallium arsenide is formed with the incorporation of high concentration silicon atoms using the reduction-projection laser doping system. In the electroplating process, high-contrast selective depositions of copper thin films have been obtained. The contrast ratio of selective deposition is estimated to exceed 107, calculated as the ratio of the current densities on the doped and undoped semiconductor surfaces. The contact between the deposited copper thin film and gallium arsenide has revealed ohmic characteristics. The specific contact resistance is estimated to be 2.32×10-5ohm-cm2, which is about 1/30 as small as that of the conventional alloyed ohmic contacts.
