Bipolar transistor and method of making a bipolar transistor

A method of making a bipolar transistor, the method comprising:

• providing a semiconductor substrate that includes a major surface, one or more layers located beneath the major surface for forming an intrinsic base of the bipolar transistor, and a collector located beneath the one or more layers;
• depositing a first oxide layer on the major surface;
• depositing a second oxide layer on the first oxide layer;
• depositing an extrinsic base layer on the second oxide layer;
• forming an emitter window through the extrinsic base layer;
• removing at least a part of the second oxide layer to form a first cavity between the first oxide layer and the extrinsic base layer;
• forming an initial part of a base link region in the first cavity;
• removing at least a part of the first oxide layer to form a second cavity between the major surface and the initial part of the base link region;
• filling the second cavity to form a completed base link region from the initial part of the base link region and the filled cavity;
• and
• forming an emitter in the emitter window.

A bipolar transistor manufactured by a method comprising:

• providing a semiconductor substrate that includes a major surface, one or more layers located beneath the major surface for forming an intrinsic base of the bipolar transistor, and a collector located beneath the one or more layers;
• depositing a first oxide layer on the major surface;
• depositing a second oxide layer on the first oxide layer;
• depositing an extrinsic base layer on the second oxide layer;
• forming an emitter window through the extrinsic base layer;
• removing at least a part of the second oxide layer to form a first cavity between the first oxide layer and the extrinsic base layer;
• forming an initial part of a base link region in the first cavity;
• removing at least a part of the first oxide layer to form a second cavity between the major surface and the initial part of the base link region;
• filling the second cavity to form a completed base link region from the initial part of the base link region and the filled cavity;
• and
• forming an emitter in the emitter window.