The structure and properties of metal-semiconductor interfaces

Measurements of lattice parameters and compositions for In1−xGaxAsyP1−y lattice matched to InP demonstrate the validity of Vegard’s law for this quaternary. The measured compositional dependence of the band gap shows a bowing parameter smaller than predicted from the previously measured band gaps of the four constituent ternaries.

Band gap versus composition and demonstration of Vegard’s law for In1−xGaxAsyP1−y lattice matched to InP

Receiver design for high-speed ptical-fiber systems

The technology of optical-fiber systems is advancing rapidly. Parallel to the development of long-haul telecommunication systems in the gigabits per second data rates operating in the long-wavelength region is the wide penetration of optical-fiber systems in local area networks, video trunking and distribution, sensors, etc. These diversified applications impose different and often conflicting constraints on the optical receiver. This paper re-examines the optical receiver design in view of these different requirements, namely, high receiver sensitivity, wide dynamic range, transparent to the operating bit rate, unrestricted data format, and fast acquisition time. Design tradeoffs between conflicting receiver requirements are considered in detail. In particular, the sensitivity of high-capacity long-wavelength transmission systems is emphasized. The state-of-the-art performance of photodetectors and low-noise amplifiers is discussed. We show that dark current of avalanche photodiodes (APD's) is the main factor limiting the sensitivity of long-wavelength optical receivers. In addition, as an example, we report on the design and experimental performance of a hybridized low-noise optical receiver amplifier capable of more than 2-Gbits/s operation. The input noise spectral density achieved is 9 pA/ \sqrt{Hz} with a noise corner frequency of 920 MHz, corresponding to an equivalent noise resistance of 120 Ω.

Receiver design for high-speed optical-fiber systems

We present the fabrication and characterization of metal-semiconductor-metal (MSM) photodiodes using the same undoped GaAs layer that is used as a buffer layer in the epitaxial structure for GaAs field effect transistors (FET's). To study the dark current mechanism, various metal electrodes used for Schottky contacts are examined. A drastic V-shape relationship between the dark current of MSM photodiode and the Schottky barrier height is found. An extremely low dark current (a few nanoamperes) in the MSM photodiode is obtained by using tungsten silicide as electrode metal. It is concluded that the dark current is a function of a rivalry relation between the electron injection at the cathode and the hole injection at the anode. The internal gain of the MSM photodiode with tungsten silicide contacts is found, and possible mechanisms are discussed. A flat frequency response up to 1.3 GHz is obtained. The results shows the feasibility of MSM photodiodes for use as photodetectors with low minimum detectable power, and their applicability to monolithic integration with FET circuits.

Low dark current GaAs metal-semiconductor-metal (MSM) photodiodes using WSi x contacts

The first operation of an integrated p-i-n-photodiode/f.e.t.-amplifier on a single wafer of In0.53Ga0.47As grown lattice matched to an InP substrate is reported.

Integrated In0.53Ga0.47As p-i-n f.e.t. photoreceiver

A two‐phase supercooled solution method is described for the LPE growth of In1−xGaxAsyP1−y on 〈100〉 InP over the entire range of lattice‐matched compositions, 0⩾y<1, 0?x<0.47. Liquid and solid compositions, distribution coefficients, and band‐gap data which may be used to design specific devices are presented.

Liquid phase epitaxial In1−xGaxAsyP1−y lattice matched to 〈100〉 InP over the complete wavelength range 0.92⩽λ⩽1.65 μm

We show that Raman scattering by LO phonons and their coupled modes can be used to obtain quantitative information on the band bending at surfaces or interfaces of doped III–V semiconductors. We have studied Schottky barrier formation and effects related to surface photovoltage at etched <111≳B surfaces of InP. These experiments yield information similar to that obtained from photoemission and photovoltage measurements, but they can also be carried out on surfaces which are contaminated or even covered with partially transparent layers such as metallic films.

Raman scattering studies of surface space charge layers and Schottky barrier formation in InP

Hall mobility measurements for the alloy III–V quaternary material In1-x}Gax}Asy}P1-y} lattice matched to semi-insulating InP substrates are described. For samples spanning the entire compositional range, the carrier concentration varied from 0.4x1016} to 1017}cm−3 and the room temperature mobilities varied from 3800cm2}/Vsec up to 11,000cm2}/Vsec. Temperature variation of the mobility in the range from 80K to 300K was investigated for selected samples. The results demonstrate that disorder scattering makes a significant contribution to limiting the mobility for material spanning the midrange (y∼0.5).

Compositional dependence of the electron mobility in In l-x Ga x As y P 1-y

Preliminary results are reported for the operation of a junction field-effect transistor fabricated from In 0.53 Ga 0.47 As grown lattice-matched to an InP:Fe substrate.

A. A. Ballman

Papers

Integrated In0.53Ga0.47As p-i-n f.e.t. photoreceiver

Liquid phase epitaxial In1−xGaxAsyP1−y lattice matched to 〈100〉 InP over the complete wavelength range 0.92⩽λ⩽1.65 μm

Raman scattering studies of surface space charge layers and Schottky barrier formation in InP

Compositional dependence of the electron mobility in In l-x Ga x As y P 1-y

An In 0.53 Ga 0.47 As junction field-effect transistor