| 摘要 |
PURPOSE:To remarkably improve element integration without impairing the performance with respect to the precision of resistance value which is requested as an intergrated circuit by using properly two kinds of resistance elements i.e. monocrystal and polycrystal. CONSTITUTION:There exist difficulties in improving element integration for monocrystal resistance. For example, the addition of P-type impurity to an N epitaxial layer is simultaneously conducted with the P base formation of transistor, the resistance value of base layer will not optionally be selected in order to minimize the configuration of resistance elements. Furthermore, the formation of the connection part with an insulating region or wires is required. Polycrystal resistance is extremely effective for the improvement of element integration. However, the precision of resistance value and that of resistance ratio vary widely by product lot as compared to monocrystal resistance. Monocrystal resistance is preferable for limiting the characteristics with respect to the resistance value within the tolerance range. Therefore, layout is easy, integration is improved and related performance is not deteriorated by using polycrystal resistance for internal logic circuits and monocrystal resistance for output logic circuits on semiconductor substrates forming large scale logic ICs. |
