A photoreceiver is usually used for a high sensitive optical fiber communication system or the device where a high output is needed to drive some electronic load circuit. In the past, most of the photoreceivers are prepared based on III-V compound material. These photoreceivers can be operated in low voltage and high wavelength, and are advantaged in having high photo absorption coefficients.
However, a conventional photoreceiver is constructed by a combination of a PIN photodiode and a filed effect transistor (FET), or a modulation doped FET (MODFET). Such a structure needs complex processes such as the molecular beam epitaxy and the liquid phase epitaxy (LPE), etc. Furthermore, the temperature for manufacturing the PIN element is so high that it will change the characteristic of the FET element, which serves as an amplifier. Manufacturing the FET element is too expensive to be applied on a large area optoelectronic integrated circuit (OEIC). Furthermore, the output current of the FET or MOFET is very low. Accordingly, if the current is used to drive the external load device, a further amplifier stage is necessary which will increase the cost and lower the system speed.
Moreover, the insulating layers of the conventional MISS structure are formed by high-temperature processes, and can be silicon oxide (formed at 1000-1100.degree. C.), silicon nitride (formed at 700-900.degree. C.) or polysilicon (formed at 700-900.degree. C.). The high temperature will influence the characteristic of the semiconductor under the insulating layer. The other devices formed before the formation of insulating layer may also be damaged by the high manufacturing temperature.
It is therefore attempted by the Applicant to solve the above-mentioned problems.