Monolithic integration of InP-Based HEMT and MSM photodiode using InGaAsP (lambda=1.3 mu m) buffer

Abstract

A new epitaxial layer structure for the integration of a high-electron-mobility transistor (HEMT) and a metal-semiconductor-metal photodiode (MSM PD) is proposed. With the aid of an InGaAsP (lambda = 1.3 mu m) buffer, this epitaxial layer structure has an additional function of light absorption without performance degradation of the HEMT. With this light absorption ability, the epitaxial layer structure can support a MSM PD structure and makes the fabrication process of the MSM PD identical to that of a HEMT. The characteristics of a monolithically integrated HEMT and MSM PD are presented and discussed. Measured f(t) and f(max) are 18.7 GHz and 47 GHz, respectively, for the 1.5 x 100 mu m(2) gate HEMT, and a responsivity of 0.7 A/W at a wavelength of lambda = 1.3 mu m has been acquired for the MSM PD.