This dissertation outlines the study and development of a Solid-state Impact-ionization Multiplier (SIM). The SIM is a stand-alone current amplifier designed with optical detection systems in mind. The SIM amplifies signals utilizing impact ionization as a source of gain. The SIM is fabricated on silicon in order to take advantage of its favorable impact ionization coefficients. Utilizing silicon in impact ionization based gain devices makes low noise and high gains attainable. Because it is a stand-alone device, it can be wired to an arbitrary current source making it capable of receiving an input from photodiodes of any material. This makes it possible to amplify a signal from a photodiode that has been optimized for a given wavelength. In this way, the SIM attempts to separate the absorption and multiplication portions in modern day optical detection/amplification devices such as in Avalanche Photodiodes (APDs). This flexibility allows it to be utilized in many different systems. The SIM has gone through several iterations in the last few years. Each change has been with the purpose of increasing gain, frequency response or yield. The progression of the device has come at the hand of much thought, theory, simulation, fabrication, and testing. One of the challenges encountered in its development has been gain controllability due to poor carrier confinement and premature breakdown. Increased gain control was developed through simulation and fabrication of a confining oxide layer. Yield and difficulties in consistent fabrication were also addressed by altering the input metallization and doping processes. The frequency response of the device has been the largest challenge in device development. Issues such as space charge, floating node voltage, edge effects and low signal amplification have caused limitations. Successes and attempts at overcoming these, and other, challenges is the basis of this dissertation of work.



College and Department

Ira A. Fulton College of Engineering and Technology; Electrical and Computer Engineering



Date Submitted


Document Type





amplifier, solid-state, impact ionization, avalanche breakdown