Abstract-A well-controlled low-temperature process, demonstrated from 350• C to 500 • C, has been developed for epitaxially growing elevated contacts and near-ideal diode junctions of Aldoped Si in contact windows to the Si substrate. A physicalvapor-deposited (PVD) amorphous silicon layer is converted to monocrystalline silicon selectively in the contact windows by using a PVD aluminum layer as a transport medium. This is a solid-phase-epitaxy (SPE) process by which the grown Si is Al-doped to at least 10 18 cm −3 . Contact resistivity below 10 −7 Ω · cm 2 is achieved to both p − and p + bulk-silicon regions. The elevated contacts have also been employed to fabricate p + -n diodes and p + -n-p bipolar transistors, the electrical characterization of which indicates a practically defect-free epitaxy at the interface.

Abstract-With a very straightforward (low-cost) process flow as basis, fully-implanted washed-emitter-base (WEB) NPN's have been optimized for operation in the 10-30 GHz range. Above 20 GHz the best overall performance is achieved by heavy doping of the epi. A low-stress silicon rich nitride layer is proven effective as surface isolation before contact window dip-etch.

Abstract-This paper reviews special RF/microwave silicon device implementations in a process that allows two-sided contacting of the devices: the back-wafer contacted Silicon-On-Glass (SOG) Substrate-Transfer Technology (STT) developed at DIMES. In this technology, metal transmission lines can be placed on the low-loss glass substrate, while the resistive/capacitive parasitics of the silicon devices can be minimized by a direct two-sided contacting. Focus is placed here on the improved device performance that can be achieved. In particular, high-quality SOG varactors have been developed and an overview is given of a number of innovative highly-linear circuit configurations that have successfully made use of the special device properties. A high flexibility in device design is achieved by two-sided contacting because it eliminates the need for buried layers. This aspect has enabled the implementation of varactors with special 2 doping profiles and a straightforward integration of complementary bipolar devices. For the latter, the integration of AlN heatspreaders has been essential for achieving effective circuit cooling. Moreover, the use of Schottky collector contacts is highlighted also with respect to the potential benefits for the speed of SiGe heterojunction bipolar transistors (HBTs).

A solid phase epitaxy (SPE) technique was developed to grow p+ aluminum-doped crystalline Si in a fully CMOS compatible process. This paper describes the experimental conditions leading to the selective growth of nanoscale single crystals where the location and dimensions are well controlled, even in the sub-100 nm range. The SPE Si crystals are defined by conventional lithography, show excellent electrical characteristics, and are uniform over the whole wafer. Fifty nanometer thick p+ SPE Si crystals were used to fabricate p+-n diodes and p+-n-p bipolar junction transistors. The high quality of the SPE Si and the remarkable control of the whole process, even in the sub-100 nm range, make this module directly usable for Si-based nanodevices.

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