Germanium Gate PhotoMOSFET Integrated to Silicon Photonics

Abstract

This paper presents a novel germanium gated NMOS phototransistor integrated on a silicon photonics platform on silicon-on-insulator (SOI) substrate. The phototransistor is fabricated with a modified NMOS process flow, with germanium which is recrystallized using rapid melt growth during the source/drain activation anneal step. The resulting device, with 1-μm channel length, and 8-μm channel width, demonstrates a responsivity of over 18 A/W at 1550 nm with 583 nW of incident light. By increasing the incident power to 912 μW, the device operates at 2.5 GHz. Miniaturization is expected to improve both responsivity and speed in future devices.

Silicon and Group IV Photonics

“…Therefore, many research activities [32,33] have focused to integrate the photodiodes monolithically with complementary metal-oxide-semiconductor (CMOS) receiver circuitry [34].…”

32 GHz germanium bipolar phototransistors on silicon photonics

“…To solve this one can simply eliminate the wire between photodiode and first stage transistor by creating a phototransistor. Several groups have recently attempted this in germanium demonstrating MOSFET [3], JFET [4], and bipolar phototransistors [5]. Unfortunately all have so far suffered from drawbacks related to low gain or low bandwidth.…”

Simulations of Ge based optically controlled field effect transistors

“…The expected advantages of the OCFET are low power, device scalability, monolithic integration with electronics and no need of frontend, with expected benefits in integrated optical receivers, optical clock distribution and on-chip optical interconnects. Devices with promising performances in terms of high frequency and sensitivity have been demonstrated [2][3][4], however, both physical effects and device operation has not been fully analyzed and there are still unsolved issues. In this work we investigate both static and dynamic characteristics of an OCFET based on a MOSFET transistor with a Ge gate using TCAD (Technology Computer Aided Design).…”