STANDARD PROCESS OVERVIEW The standard 25V analog bipolar process is specifically designed to satisfy the requirements of matched pair NPN superbeta transistors. The process is a complete BJT process (bipolar juncton isolated transistor process). The degree of matching of various device characteristics are collector current, temperature and layout design dependent. Protection diodes and biasing resistors may be also integrated for demanding custom applications. The 25V analog bipolar process for matched pair NPN superbeta transistors employs  N type silicon epitaxial layer on  P type silicon substrate. In the standard process up to 8 masks are used: - buried layer (sub collector), isolation, base, emitter, contact mask, thin film resistor mask, metal mask, pad mask. The devices available are vertical NPN transistors, TaN2 - tantalum nitride  thin film resistors.

PROCESS OPTIONS are available with the standard 25V analog bipolar process for high voltage IC. Process options-enhancements are added to increase the integrated circuit designer's flexibility in designing with  HTE Labs analog bipolar process. Optional devices available are as follows: P JFET (p channel junction field effect transistor ), EPI N JFET (n channel silicon epitaxial junction field effect transistor ) , Schottky diodes,Varactor diodes, PIN diodes,Zenner diodes, laser trim able NiCr (nickel chrome resistors) , TaN2 ( tantalum nitride resistors ) or SiCr ( silicon chrome resistors ) sputtered  thin film resistors. Sheet resistance for  the integrated thin film resistors is offered in the widest range from 1ohm / square to 100k ohms / square while the temperature coefficient of resistance is between ± 25 ppm/°C to ± 500ppm/°C.

For metal interconnections HTE Labs process employs up to two layers of metallization, TiW/Au (standard metallization). The interlayer dielectric is 1mm SiO₂ while the passivation is Si₃N₄ or SiO₂. Minimum contact size is 3mm x 3mm while the metal pitch is 10mm. For flip chip, chip on board and chip scale packaging applications, Gold bumps or solder bumps are available process options. The 25V custom analog bipolar process employs up to 12 masking layers for all features to be included. What sets HTE Labs apart are couple main process options and capabilities that are not typically acceptable or handled by large wafer foundries:

 0)- Custom developed processes HTE Labs has the engineering resources and processing capabilities to develop custom processes to fit customer's specific applications. This capability is offered to customers on a contract base only.
1)- High stability thin film resistors with sheet resistance as high as 100Kohms/square. The matching of the as deposited thin film resistors is excellent with ought expensive laser trim. The absolute values of resistors are  within ± 5% across the wafer and from wafer to wafer. For high speed RF IC process applications, thin film resistors are best suited due to their very low capacitance and low noise.
2)- High reliability gold metal interconnections  is a standard process feature specifically designed for hybrid circuits applications, chip on board applications and sensors that need to withstand corrosive environment where aluminum or copper metallization are not a suitable choices.
3)- MEMS smart sensor integration  KOH anisotropic etch, deep RIE etch, LPCVD polysilicon and front to back mask alignment are few process enhancements that are needed in developing and manufacturing of integrated smart pressure sensors, accelerometers and other as such.
4)- Optoelectronic integrated circuits Photo transistors, photodiodes and low capacitance high speed PIN diodes, when integrated with the bipolar process, allow increased flexibility to design and manufacturing of fiber optic amplifiers, optocouplers or optical switches.

Analog Bipolar process - 4" wafer foundry services
At this time HTE Labs offers only 4" wafer fabrication for the analog bipolar wafer foundry services. HTE Labs wafer fab specializes in prototypes and  small runs of standard and custom developed analog bipolar processes. Customer's own tooling can be used in most of the cases provided that design rules are compatible with current processes. For more information or a request for quote, please contact HTE Labs now, preferably in writing by fax or by e-maill: HERE