PURPOSE: To obtain easily desired capacity vs. voltage characteristics of the variable capacity diode device by forming at least one diffused layer of higher abrupt P-N junction forming the diode of a plurality of diffused layers having different areas in plane sequentially formed in thicknesswise direction of an epitaxial layer.
CONSTITUTION: An N type layer 8 is epitaxially grown on an n+ type semiconductor substrate, an N type impurity is diffused to forming a variable capacity diode used for a high frequency tuning circuit and a local oscillating circuit, and N type regions 10, 9 are formed. The regions 10, 9 are formed of respective layers 1∼6 and 1'∼6' while varying the dose to 2×1011∼1×1014pieces/cm2 at every layer to form super abrupt P-N junction. At this time the regions 10 used for the high frequency tuning circuit are formed to have same area in the respective diffused layers. The regions 9 for the local oscillating circuit are altered in size of the opening of the mask to 870∼1,035μm at every diffusion, and there is formed a difference in the plane areas of the respective layers 1∼6. Thereafter, p+ type regions 7, 7' are diffused on the uppermost layers 6, 6' respectively.
MATSUMOTO KOUJI
HANABUSA MITSURU
AIZU TOUKOU KK
| JPS526476A | 1977-01-18 | |||
| JPS5218667B2 | 1977-05-23 |