SEMICONDUCTOR DEVICE HAVING PHOTODETECTOR AND OPTICAL PICKUP SYSTEM USING THE SAME

摘要

A semiconductor device includes a photodetector having ajunction at which a first conductive type firstsemiconductor portion and a second conductive type secondsemiconductor portion are joined to each other. In thisphotodetector, division regions are formed in part of thefirst semiconductor portion in such a manner as to crossthe first semiconductor portion and partially enter thesecond semiconductor portion, so that the junction isdivided into a plurality of parts by the division regions,to form a plurality of photodetector regions having thedivided junction parts. When a reverse bias voltage,which is equal to or less than a specific reverse biasvoltage applied to the divided junction parts uponoperation of the photodetector, is applied to the dividedjunction parts, depletion layers originated from twodivided junction parts, disposed on both the sides ofeach of the division regions, of the plurality of dividedjunction parts extend, in the second semiconductorportion, under the division region to be brought intocontact with each other. With this configuration, thefrequency characteristic and the light receivingsensitivity of the photodetector are improved.