Method of making a low parasitic resistor on ultrathin silicon on insulator
First Claim
1. A method for forming a diffused resistor comprising the steps of:
- providing an insulating substrate;
forming a thin semiconductor layer on the insulating substrate wherein the thin semiconductor layer has a maximum fixed charge density of no more than about 5×
1011 cm-2 ;
providing any resistor implants in a resistive region of the thin semiconductor layer wherein the any resistor implants are for setting a resistance of the diffused resistor;
preventing any implants other than the any resistor implants from being provided in the resistive region;
forming in the thin semiconductor layer a first contact region and a second contact region wherein the first contact region is electrically coupled to the resistive region by being contiguous with a first portion of the resistive region and wherein the second contact region is electrically coupled to the resistive region by being contiguous with a second portion of the resistive region.
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Accused Products
Abstract
A diffused resistor and a method for making the diffused resistor are disclosed. The diffused resistor is formed in a substantially pure portion of the thin semiconductor layer that is formed on an insulating substrate. The thin semiconductor layer has low a number of defects and mid-band gap states. This portion may be located in an electrically isolated region of the thin semiconductor layer. A resistive region is used to provide the resistance of the diff-used resistor. Contact regions are provided continguous with the the resistive region. The diff-used resistor can be formed by themselves or in conjunction with other circuit elements, such as a MOSFET, for example. Accordingly, also disclosed is a method for making the diffused resitor in conjunction with a MOSFET. The diffused resistor and the MOSFET are formed in electrically isolated semiconductor islands. The electrically isolated semiconductor islands are formed from the high quality thin semiconductor layer. Both non-silicide and silicide processes are disclosed. Also disclosed is a differential amplifier circuit that uses the disclosed diffused resistor embodiments.
180 Citations
39 Claims
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1. A method for forming a diffused resistor comprising the steps of:
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providing an insulating substrate; forming a thin semiconductor layer on the insulating substrate wherein the thin semiconductor layer has a maximum fixed charge density of no more than about 5×
1011 cm-2 ;providing any resistor implants in a resistive region of the thin semiconductor layer wherein the any resistor implants are for setting a resistance of the diffused resistor; preventing any implants other than the any resistor implants from being provided in the resistive region; forming in the thin semiconductor layer a first contact region and a second contact region wherein the first contact region is electrically coupled to the resistive region by being contiguous with a first portion of the resistive region and wherein the second contact region is electrically coupled to the resistive region by being contiguous with a second portion of the resistive region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for forming a diffused resistor and a MOSFET in a thin semiconductor layer, the method comprising the steps of:
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providing an insulating substrate; forming the thin semiconductor layer on the insulating substrate wherein the thin semiconductor layer has a maximum fixed charge density of no more than about 5×
1011 cm-2 ;forming a first electrically isolated portion of the thin semiconductor layer and a second electrically isolated portion of the thin semiconductor layer wherein at least the first electrically isolated portion has the maximum fixed charge density of no more than about 5×
1011 cm-2 ;providing any resistor implants in a resistive region of the first electrically isolated portion of the thin semiconductor layer wherein the resistor implants are for setting a resistance of the diffused resistor; preventing any implants other than the any resistor implants from being provided in the resistive region; forming in the first electrically isolated portion of the thin semiconductor layer a first contact region and a second contact region wherein the first contact region is electrically coupled to the resistive region by being contiguous with a first portion of the resistive region and wherein the second contact region is electrically coupled to the resistive region by being contiguous with a second portion of the resistive region; forming a MOSFET in the second electrically isolated portion of the thin semiconductor layer. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification