21

Implantable Microelectronics

Mario Birkholz

IHP – Leibniz Institut für innovative Mikroelektronik, Frankfurt (Oder), Germany

CONTENTS

21.1 Introduction......................................................................................................................341

21.2 Sensor and Actuator Designs........................................................................................343

21.3 Biocompatibility...............................................................................................................346

21.4 Intelligence........................................................................................................................347

21.5 Communication................................................................................................................348

21.6 Energy Supply..................................................................................................................348

21.7 System Integration...........................................................................................................349

21.8 Ethical Aspects.................................................................................................................350

21.9 Conclusions and Perspectives.......................................................................................352

Acknowledgments......................................................................................................................352

References ....................................................................................................................................353

21.1 Introduction

A breathtaking development began with the realization of the first integrated circuits

[1–3] around 1960, which has reached a level today allowing the integration of billions of

transistors on one microchip. In the course of this development, not only were enormous

rationalization potentials in industrial processes tapped and an essential basis for the

economic prosperity of many people laid, it also opened up new business fields in in­

formation and communications technology, such as those associated today above all with

the Internet [4]. Microelectronic chips are already being used in various human implants,

and it is foreseeable that their use in the human body in the form of sensors and actuators

will become increasingly widespread.

The development of intelligent implants is essentially based on advances in micro­

electronics and its continuous miniaturization. The latter is usually referred to as

“Moore’s Law” and goes back to the observation, first published by Gordon Moore, that

the number of components used in integrated circuits doubles every 1½ to 2 years [5]. For

many years, this doubling was possible due to the so-called scaling of CMOS technology

(complementary metal-oxide-semiconductor), as first described in 1974 by Dennard et al.

for the MOS field-effect transistor MOSFET [6]. This observation gave Moore’s law the

character of a self-fulfilling prophecy since Moore had stated in his work that there were

“no comparable limits to the degree of integration as in thermodynamic processes.” It

is true that in the leading semiconductor factories, scaling is no longer reflected in the

DOI: 10.1201/9781003263265-21

341