Silicon-on Diamond Technology for Radiation Hardened Electronics

The objective of this program is to develop a silicon-on-insulator technology (SOI) using CVD diamond films as insulators. Such structures should permit the fabrication of integrated circuits with performance capabilities superior to those fabricated using conventional SOI structures including silicon-on-Sapphire (SOS), SIMOX, Epitaxial Layer Overgrowth (ELO) and Bond Etchback SOI (BESOI). Diamond insulating substrates should extend the radiation tolerance of existing SOI technologies due to their high transparency to radiation. The Silicon-on-diamond (SOD) technology is the only SOI approach that allows for efficient heat dissipation from the active regions of integrated circuits as a result of the exceptional thermal conductivity of diamond. Diamond films provide unsurpassed thermal conductivity of 20W-cm-1K-1, excellent radiation resistance of greater than 107 RAD for SOD devices and high electrical resistivity of greater than 1 x 1014 Ohm-cm. The goal of this project is to successfully fabricate SOD wafers using a wafer bonding process and to have good performance of the SOD wafers in terms of low leakage, high thermal conductivity and high radiation resistance. These performance advantages will be available for use in CMOS structures, analog circuits, BICMOS structures and radiation hard circuits. SOD wafers have application within the large SOI market where there is a demand for radiation hardness, high temperature performance and high heat dissipation from the devices. One example of the application of SOD wafers is to use them as substrates for high performance ICs used in space, in the atmosphere and on the ground. Due to the superior heat dissipation of SOD substrates, enhanced performance can be achieved in technologies such as dense bipolar integrated circuits and CMOS devices. Problems with short-channel effects and leakage in CMOS devices make a change from bulk silicon to SOD wafers desirable.