A fully complementary BiCMOS technology for 10 V mixed-signal circuit applications

Abstract

A 10 V fully complementary BiCMOS technology, HBC-10, has been developed for high speed, low noise and high precision mixed signal system integration applications. In this technology, two varieties of CMOS transistors have been implemented for 10 V analog and 5 V digital applications. A gate oxide thickness of 30 nm is utilized for the 10 V CMOS transistors with a lightly doped drain extension added to the NMOS structure to achieve device lifetime in excess of 10 years. A gate oxide thickness of 18 nm is used for 5 V CMOS logic circuits. These transistors are specially architected so that they may also serve as analog transistors in 5 V circuit applications. The 5 V NMOS transistor lifetime is guaranteed by use of a double diffused drain structure. The active devices are isolated by a fully recessed 1.5 /spl mu/m oxide grown under high pressure conditions. Use of high pressure steam, plus combining diffusion operations where possible, results in a low overall thermal budget. This allows the up-diffusion of buried layers to be minimized so that a thin, 1.6 /spl mu/m epitaxial silicon layer is sufficient to support 10 V bipolar transistors. The resultant vertical PNP and NPN transistors are characterized with cut-off frequencies of more than 1.3 GHz and 5 GHz, respectively. Likewise, the associated products of the current gain and Early voltage of PNP and NPN bipolar transistors are more than 1000 and 6000 V, respectively. A precision, buried Zener diode (for voltage reference applications), PtSi Schottky diode, polysilicon-oxide-polysilicon capacitor and trimmable thin film resistor are integrated into this process. This wide variety of passive and active components is essential for system integration and has been carefully designed for precision analog applications. The total number of masking operations is 23, which includes double layer metallization.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>