Nuclear Instruments and Methods in Physics Research A 570 (2007) 317–321 First electrical characterization of 3D detectors with electrodes of the same doping type Alberto Pozza a,Ã , Maurizio Boscardin a , Luciano Bosisio b , Gian-Franco Dalla Betta c , Claudio Piemonte a , Sabina Ronchin a , Nicola Zorzi a a Divisione Microsistemi, ITC-irst, Via Sommarive 18, I-38050 Povo, Trento, Italy b INFN and Dipartimento di Fisica, Universita` di Trieste, Via A. Valerio, 2, I-34127 Trieste, Italy c INFN and Dipartimento di Informatica e Telecomunicazioni, Universita` di Trento, Via Sommarive 14, I-38050 Povo, Trento, Italy Available online 2 October 2006 Abstract The 3D silicon radiation detectors are very promising devices to be used in environments requiring extreme radiation hardness, such as the super-LHC experiment at CERN. A drawback of this detector is the very long and non-standard fabrication process, which makes the mass production of these devices very critical. A possible simplification of the manufacturing process relies on a new type of 3D architecture, called 3D-single-type-column detector, that we have introduced in previous works. In this paper we report on the fabrication process of the first batch of detectors and on selected results from the electrical characterization of 3D test structures, covering leakage current, capacitance and breakdown voltage measurements. r 2006 Elsevier B.V. All rights reserved. PACS: 29.40.Wk; 29.40.Gx; 85.30.De Keywords: Silicon detectors; Fabrication technology; Electrical characterization; 3D detectors; DRIE etching 1. Introduction In the mid-nineties a new architecture of silicon radiation detectors, called 3D detector, was proposed [1], which involves the fabrication of the electrodes deep inside the silicon wafer. This detector concept has soon given rise to a great interest because of its intrinsic advantages over standard planar detectors. Indeed, due to the fact that the electrode distance depends on the layout, rather than on the wafer thickness, it is possible to shorten the electrode distance allowing for low depletion voltage and fast charge collection times. It is important to note that, differently from thin detectors, this is obtained without reducing the amount of signal charge released by a particle, that scales with the substrate thickness. In heavily irradiated planar detectors the increase of the depletion voltage and the reduction of the charge carrier mean drift length due to trapping effects are a major issue [2]. In 3D detectors, a direct consequence of the low depletion voltage and short distance between electrodes is an increase of the radiation tolerance. A drawback of 3D detectors is the rather long and complex fabrication process, as methods of silicon micro- machining must be used. This could lead to the unfeasi- bility of mass production of these detectors. In our previous works [3,4] we described a new architecture of 3D detector, called 3D-single-type column (3D-stc), whose main purpose is the simplification of the fabrication process. This device consists of columnar electrodes of one doping type only, e.g., n + columns on a p-type substrate, which is the case of our first production batch. Owing to the single column etching and doping step, the fabrication process of these devices is much simpler. Moreover, if columns are only partially etched through the wafer thickness, an additional simplification is related to the fact that no support wafer during processing is necessary and the ohmic electrode can be obtained by ARTICLE IN PRESS www.elsevier.com/locate/nima 0168-9002/$ - see front matter r 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2006.09.032 Ã Corresponding author. Tel.: +39 0461 314438; fax: +39 0461 302040. E-mail address: albpozza@itc.it (A. Pozza).