| 摘要 |
PURPOSE:To use a silicon nitride film as a field plate as well by forming a silicon nitride film by the method of magnetron sputtering, using single crystal silicon as a target and the mixture gas of nitride and argon as sputtering gas and making the composition ratio of nitride below 60%. CONSTITUTION:MOSFET comprises a drain 9, a source 10, a gate electrode 11, a source electrode 12, a silicon nitride SiO2 film 5, a protective film 7b consisting of silicon nitride, and a depletion layer 4B made in said drain 9. The protective film 7b is adjusted as under. The silicon nitride protective film is formed, using the mixture gas of nitrogen and argon gas as sputtering gas and single crystal silicon as a target. When the composition ratio of nitride exceeds 60%, the protective film consisting of silicon nitride is of the composition near to the stoichiometric composition (N/Si is 1.33 in Si3N4). Where the composition ratio of nitrogen is below 60%, it is of the composition that the silicon is excessive, in which N/Si is becomes smaller than 1.33. when the silicon becomes excessive, conductivity occurs. |
