Gm Global Technolgoy Operations, Inc.

Eugene Greenstein

Bernard A MacIver

A monolithic integrated circuit structure having an integral high value surge protection resistor of polycrystalline silicon on a thermally grown thick silicon dioxide plateau having no surface diffusion regions thereunder. The structure can be made by merely adding intermediate steps to existing integrated circuit processing. It is capable of absorbing transients of hundreds of volts.

Integrated circuit process compatible surge protection resistor

Low dosage phosphorus implantation regions in &lt;100&gt; P-type silicon are subjected to a severe damage implant with halogen or silicon ions, preferably fluorine and chlorine. This permits anneal in a strongly oxidizing atmosphere for PN junction passivation, without concurrently inducing PN junction leakage. Oxide passivated PN junctions are formed having leakages as low as when the low dose phosphorus implants are annealed in other atmospheres, or are formed in &lt;111&gt; silicon.

Method of low dose phoshorus implantation for oxide passivated diodes in

Boron implantation regions in &lt;100&gt; N-type silicon are subjected to a severe damage implant before anneal in a strongly oxidizing atmosphere that provides a passivating silicon dioxide surface layer. Diodes are formed having leakages as low as when such regions are annealed in other atmospheres or are formed in &lt;111&gt; silicon. In a preferred example, BF.sub.2.sup.+ is used to simultaneously implant boron into a region and convert it to amorphous silicon.

Method of forming diodes by amorphous implantations and concurrent

An improved method of making bipolar monolithic integrated circuits by successive diffusions of boron and phosphorus. Selective halogen ion implantation is used to locally specifically enhance phosphorus diffusion. The halogen implant is performed prior to the boron diffusion. Enhanced local phosphorus diffusion provides selected transistors in the circuit with a narrower base width than others, and a corresponding higher current gain than others. Analogously, higher value pinch resistors can be selectively produced in the circuit.

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Southfield, MI, United States of America

Eugene Greenstein