Thick microporous silicon isolation layers for integrated RF inductors

Abstract

In this paper, we present processes to etch high thickness porous silicon layers for RF device applications. Indeed, on‐chip inductors realized on bulk silicon suffer from mediocre Q‐factor values mainly because of electrical losses into the substrate and capacitive coupling with the silicon appearing beyond 1 GHz. We present a detailed study of etching parameters such as the current density or the HF concentration in HF: H2O:acetic acid based electrolytes. In addition, we propose a prospective study of integrated copper inductor performances on porous silicon substrates in the range of 100 MHz to 10 GHz. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thermal conductivity measurement of porous silicon by the pulsed-photothermal method

“…In this work, the apparent thermal conductivity of two types of porous Si is determined by the photothermal nanosecond method [15,16]. The rst one is fabricated with the sintering technique with pores diameter varying between 100 nm and 1000 nm [17] and the other one has its pores diameter very small, varying between 5 nm and 10 nm and it has been elaborated by electrochemical etching [18]. The advantage of this method is the ability to compare the thermal conductivity of porous Si having two dierent sizes of pores in order to estimate the relation between these parameters.…”

Supercritically-Dried Porous Silicon Powders with Surface Areas Exceeding 1000 m2/g

“…The super-critical drying technique -a scalable process in itself -can also be applied at the wafer-scale level, for porous silicon thin films attached to wafer substrates, which might also be of benefit for applications such as microthrusters, 6 energetics, 4 energy storage, 8 and RF devices. 30…”

Microporous Silicon

“…They have been utilized in bacterial culture (Wainwright et al 1999) and when in simulated body fluids can promote calcification, of relevance to orthopedic use (Canham 1995). Thick layers of moderate porosity are also under study for RF device applications where high electrical resistivity is desired (Gautier et al 2008).…”