| 摘要 |
PURPOSE:To contrive to reduce the series resistance of a device having electrode lead-out diffused layers of different depths by a method wherein a shallow impurity diffused layer is provided after a deep impurity diffused layer is first formed. CONSTITUTION:When an oxide film 23 is removed from an N type Si substrate 21, an oxide film 22 is selectively opened window 24, an N type impurity is diffused at a high density, and thus N<+> layers 25 and 26 of the depth approx. 10mum are formed, oxide thin films 27 and 28 are simultaneously formed. Next, the film 22 is opened window by applying a resist mask on the oxide films 22 and 27, and then a film 28 is removed by etching. It is covered with a BSG29, heat-treatment is performed by superposing an undoped oxide film 30, and B is diffused from a film 29, resulting in the formation of a P<+> layer 31. The films 29 and 30 are removed, Au is vapor-deposited on the layers 31 and 26, an Au-Si eutectic electrode is provided by high temperature treatment, and accordingly a P-I-N diode is completed. Since the layer 26 necessary for deep diffusion is formed first, a steep impurity profile can be formed, the resistance of the layer 31 is kept sufficiently low, and the surface density high, thus the contact resistance can be reduced; the diffusion into an I layer 21 by Au is prevented, and the increase of the series resistance is not generated. |
