Study and characterization of porous germanium for radiometric measurements

Abstract

The aim of this article is to study and realize a new detector based on a porous germanium (pGe) photodiode to be used as a standard for radiometric measurement in the wavelength region between 800 nm and 1700 nm. We present the development and characterization of a porous structure realized on a single‐crystal substrate of p‐type germanium (Ga doped) and of crystallographic orientation (100). The obtained structure allows, on the one hand, to trap the incident radiation, and on the other hand, to minimize the fluctuations of the front‐face reflection coefficient of the photodiode. The first studies thus made show that it is possible to optimize, respectively, the electrical current density and the electrochemical operation time necessary for obtaining exploitable porous structures. The obtained results show that for 50 mA/cm2 and 5 min as operational parameters, we obtain a textured aspect of the porous samples that present a pyramidal form. The reflectivity study of the front surface shows a constant value of around 38% in a spectral range between 800 nm and 1700 nm approximately. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Development and characterization of a ZnO/Ge photodiode for optical radiation measurements in the near infrared

“…These substrates have a reflectivity of about 33% for the wavelength range between 800 nm and 2000 nm [1,2]. Ion implantation is performed by the ion implanter installed in Microelectronics Institute of Barcelona in Spain.…”

“…Research work carried out within the metrology group of radiometric and pyrometric measurements of INSAT, have achieved NP junctions by ion implantation from Ge p-type substrate and the realization of porous germanium photodiodes [1][2][3]. These studies have shown an improvement in the absorption of the incident light with respect to the commercial photodiodes based on the junction germanium.…”

Macroporous Semiconductors

“… Practically all applications discussed so far use porous Si. Microporous Ge might find applications [ 30 , 175 ] but so far very little has been proposed with respect to applications of porous III-V’s [ 176 , 177 ]. Some proposed applications, while perfectly viable, are rather impractical.…”

Shallow V-Shape Nanostructured Pit Arrays in Germanium Using Aqua Regia Electroless Chemical Etching

“…While many low-cost nano-texturing processes were pioneered for silicon [ 15 , 16 , 17 , 18 , 19 ], researchers have been searching for an equivalent approach to achieve uniform and low-cost anti-reflection for bulk Germanium. Some earlier reports focused on electrochemical etching [ 20 , 21 , 22 , 23 , 24 ], where electric fields are used to drive the reaction. Different types of etching agents for various concentrations and etching times were used and encouraging results were achieved using this process [ 20 ].…”

“…Since no good electroless recipe was found, we went back to the roots of chemical wet etching for microelectronics. With the push to develop microelectronics, researchers quickly sought low-cost chemical etching processes to achieve uniform cleaning and etching [ 2 , 20 , 22 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. Early works quickly converged around two main standard cleaning (SC) protocols pioneered in the late 1960s and early 1970s [ 25 , 33 ].…”